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245 results on '"S. Gushue"'

1. Participant and spectator scaling of spectator fragments in Au + Au and Cu + Cu collisions atsNN=19.6and 22.4 GeV

Author

I. Sedykh, Judith Katzy, P. Steinberg, A. S. Carroll, J. Sagerer, T. Gburek, Alice Mignerey, R. Bindel, R. Verdier, A. H. Wuosmaa, M. P. Decowski, R. S. Hollis, Christophe Pol A Roland, Adam Trzupek, S. Gushue, R. Holynski, P. Walters, J. L. Kane, George S. F. Stephans, S. Manly, G. J. van Nieuwenhuizen, Russell Richard Betts, Conor Henderson, G. A. Heintzelman, C. Halliwell, P. Sarin, Gunther Roland, K. Gulbrandsen, C. Loizides, N. Khan, I. Harnarine, W. Kucewicz, E. Richardson, N. George, E. García, P. Kulinich, W. Skulski, B. B. Back, Burt Holzman, A. Iordanova, A. Szostak, Bolek Wyslouch, Inkyu Park, S. S. Vaurynovich, Barbara Wosiek, L.J. Rosenberg, Z. Chai, Gabor Istvan Veres, Jau Tang, B. Alver, E. Johnson, Krzysztof Woźniak, Heinz Pernegger, A. Budzanowski, A. Sukhanov, Chia-Ming Kuo, Wit Busza, R. Pak, M. Ballintijn, J. Hamblen, W. T. Lin, Rachid Nouicer, D. McLeod, M. A. Stankiewicz, M. Reuter, Andrzej Olszewski, M. D. Baker, L. P. Remsberg, M. B. Tonjes, V. Chetluru, P. Sawicki, C. E. Smith, D. Willhelm, Wei Li, F. L. H. Wolfs, S. M. Wyngaardt, Edward Allen Wenger, D. S. Barton, A. A. Bickley, C. Reed, D. J. Hofman, and C. Vale

Subjects
Physics, 010308 nuclear & particles physics, chemistry.chemical_element, 01 natural sciences, Ion, Nuclear physics, chemistry, Pseudorapidity, 0103 physical sciences, Neutron, Atomic physics, Impact parameter, Nuclear Experiment, 010306 general physics, Relativistic Heavy Ion Collider, Nucleon, Glauber, Helium
Abstract

Spectator fragments resulting from relativistic heavy ion collisions, consisting of single protons and neutrons along with groups of stable nuclear fragments up to nitrogen $(Z=7)$, are measured in PHOBOS. These fragments are observed in Au+Au $(\sqrt{{s}_{{}_{NN}}}=19.6\phantom{\rule{0.16em}{0ex}}\mathrm{GeV})$ and Cu+Cu (22.4 GeV) collisions at high pseudorapidity $(\ensuremath{\eta})$. The dominant multiply-charged fragment is the tightly bound helium $(\ensuremath{\alpha})$, with lithium, beryllium, and boron all clearly seen as a function of collision centrality and pseudorapidity. We observe that in Cu+Cu collisions, it becomes much more favorable for the $\ensuremath{\alpha}$ fragments to be released than lithium. The yields of fragments approximately scale with the number of spectator nucleons, independent of the colliding ion. The shapes of the pseudorapidity distributions of fragments indicate that the average deflection of the fragments away from the beam direction increases for more central collisions. A detailed comparison of the shapes for $\ensuremath{\alpha}$ and lithium fragments indicates that the centrality dependence of the deflections favors a scaling with the number of participants in the collision.

Published
2016

2. Nucleon-gold collisions at200AGeV using taggedd + Auinteractions in the PHOBOS detector

Author

M. P. Decowski, G. J. van Nieuwenhuizen, George S. F. Stephans, Chia-Ming Kuo, N. Khan, P. Sarin, Christof Roland, M. Ballintijn, T. Gburek, P. Steinberg, J. Hamblen, F. L. H. Wolfs, Inkyu Park, D. S. Barton, Barbara Wosiek, J. Zhang, E. García, W. T. Lin, K. Gulbrandsen, A. A. Bickley, Rachid Nouicer, Adam Trzupek, D. J. Hofman, R. S. Hollis, Krzysztof Woźniak, C. Vale, S. Gushue, Gunther Roland, Heinz Pernegger, Jongmin Lee, C. E. Smith, A. S. Carroll, J. Sagerer, Russell Richard Betts, Conor Henderson, P. Kulinich, Andrzej Olszewski, M. B. Tonjes, N. George, C. Halliwell, W. Skulski, Gabor Istvan Veres, Burt Holzman, Bruce Becker, Boleslaw Wyslouch, E. Johnson, C. Reed, A. Sukhanov, Wit Busza, R. Pak, I. Sedykh, J. L. Kane, S. Manly, R. Verdier, B. B. Back, Alice Mignerey, R. Bindel, M. D. Baker, A. S. Harrington, A. Iordanova, and R. Holynski

Subjects
Physics, Nuclear and High Energy Physics, Particle physics, Proton, media_common.quotation_subject, Nuclear Theory, Hadron, Asymmetry, Nuclear physics, Deuterium, Isospin, Pseudorapidity, High Energy Physics::Experiment, Nuclear Experiment, Relativistic Heavy Ion Collider, Nucleon, media_common
Abstract

Forward calorimetry in the PHOBOS detector has been used to study charged hadron production in d + Au, p + Au, and n + Au collisions at √ sNN = 200 GeV. The forward proton calorimeter detectors are described and a procedure for determining collision centrality with these detectors is detailed. The deposition of energy by deuteron spectator nucleons in the forward calorimeters is used to identify p + Au and n + Au collisions in the data. A weighted combination of the yield of p + Au and n + Au is constructed to build a reference for Au + Au collisions that better matches the isospin composition of the gold nucleus. The pT and centrality dependence of the yield of this improved reference system is found to match that of d + Au. The shape of the charged-particle transverse momentum distribution is observed to extrapolate smoothly from p + ¯ p to central d + Au as a function of the charged-particle pseudorapidity density. The asymmetry of positively and negatively charged hadron production in p + Au is compared to that of n + Au. No significant asymmetry is observed at midrapidity.ThesestudiesaugmentrecentresultsfromexperimentsattheCERNLargeHadronColliderandBNL Relativistic Heavy Ion Collider facilities to give a more complete description of particle production in p + A and d + Acollisions,essentialfortheunderstandingthemediumproducedinhigh-energynucleus-nucleuscollisions.

Published
2015

3. PHOBOS Overview

Author

David J Hofman, the Phobos collaboration, null Bbback, M D Baker, M Ballintijn, D S Barton, R R Betts, A A Bickley, R Bindel, A Budzanowski, W Busza, A Carroll, Z Chai, M P Decowski, E García, T Gburek, N George, K Gulbrandsen, S Gushue, C Halliwell, J Hamblen, M Hauer, G A Heintzelman, C Henderson, R S Hollis, R Hołyński, B Holzman, A Iordanova, E Johnson, J L Kane, N Khan, P Kulinich, C M Kuo, W T Lin, S Manly, A C Mignerey, R Nouicer, A Olszewski, R Pak, I C Park, C Reed, C Roland, G Roland, J Sagerer, H Seals, I Sedykh, C E Smith, M A Stankiewicz, P Steinberg, G S F Stephans, A Sukhanov, M B Tonjes, A Trzupek, C Vale, G J van Nieuwenhuizen, S S Vaurynovich, R Verdier, G I Veres, E Wenger, F L H Wolfs, B Wosiek, null Kwoźniak, and B Wysłouch

Subjects
History, Computer Science Applications, Education
Published
2006

4. Particle production in nuclear collisions over a broad centrality range from the PHOBOS experiment

Author

Inkyu Park, R. Ho⌈yński, N. George, F. L. H. Wolfs, K. Gulbrandsen, C. Loizides, M. P. Decowski, D. Willhelm, P. Sawicki, A. Szostak, P. Kulinich, Bolek Wyslouch, W. Kucewicz, Burt Holzman, Chia-Ming Kuo, Andrzej Olszewski, Edward Allen Wenger, L.J. Rosenberg, R. S. Hollis, W. Skulski, A. Budzanowski, V. Chetluru, E. Richardson, M. Ballintijn, N. Khan, Wei Li, Christof Roland, David Jonathan Hofman, C. E. Smith, Russell Richard Betts, Conor Henderson, Alice Mignerey, J. L. Kane, I. Sedykh, T. Gburek, A. Iordanova, S. Manly, M. Reuter, M. D. Baker, George Stephans, J. Hamblen, R. Bindel, C. Vale, G. Van Nieuwenhuizen, S. Gushue, P. Walters, B. B. Back, Z. Chai, Rachid Nouicer, Adam Trzupek, M. A. Stankiewicz, Marguerite Tonjes, Krzysztof Woźniak, G. A. Heintzelman, Willis Lin, E. García, C. Reed, A. Sukhanov, L. P. Remsberg, S. S. Vaurynovich, Wit Busza, R. Pak, A. H. Wuosmaa, Gunther Roland, Barbara Wosiek, I. Harnarine, B. Alver, P. Sarin, A. S. Carroll, R. Verdier, C. Halliwell, S. M. Wyngaardt, Gabor Istvan Veres, Peter Steinberg, D. S. Barton, A. A. Bickley, E. Johnson, J. Sagerer, and Jaw-Luen Tang

Subjects
Physics, Nuclear physics, Factorization, Pseudorapidity, General Physics and Astronomy, Heavy ion, Atomic physics, Multiplicity (chemistry), Nuclear Experiment, Centrality, Collision, Scaling, Charged particle
Abstract

The PHOBOS collaboration has studied the pseudorapidity and transverse momentum distributions of charged particles produced in heavy ion collisions. Results from Au+Au collisions at various center-of-mass energies and over a broad range of centrality are presented here. The data are compared to Cu+Cu, p+p and d+Au collisions at corresponding energies and centralities. The data are found to exhibit simple scaling properties such as the observed factorization of collision energy and geometry dependences. The presented data help us distinguish between models of particle production in relativistic heavy ion collisions.

Published
2006

5. Ultra-relativistic <font>Au</font>+<font>Au</font> and <font>d</font>+<font>Au</font> collisions: Experimental studies by PHOBOS

Author

Alice Mignerey, R. Bindel, D. McLeod, T. Gburek, Chia-Ming Kuo, Andrzej Olszewski, I. Sedykh, G. Van Nieuwenhuizen, K. Gulbrandsen, Gunther Roland, S. Gushue, R. Holynski, H. Seals, Rachid Nouicer, Adam Trzupek, D. S. Barton, A. A. Bickley, M. Ballintijn, J. Katzy, G. A. Heintzelman, P. Kulinich, A. Sukhanov, W. Kucewicz, M. Hauer, J. Hamblen, A. H. Wuosmaa, B. B. Back, F. L. H. Wolfs, David Jonathan Hofman, Bolek Wyslouch, S. S. Vaurynovich, Willis Lin, Christof Roland, Russell Richard Betts, Conor Henderson, L. P. Remsberg, Wit Busza, N. George, Gabor Istvan Veres, C. Vale, Heinz Pernegger, Peter Steinberg, Barbara Wosiek, P. Sawicki, N. Khan, George Stephans, L.J. Rosenberg, A. Iordanova, Z. Chai, A. S. Carroll, R. Verdier, W. Skulski, Burt Holzman, E. Johnson, Marguerite Tonjes, M. Reuter, J. L. Kane, S. Manly, R. S. Hollis, Krzysztof Woźniak, M. D. Baker, Edward Allen Wenger, C. Halliwell, R. Pak, C. Reed, M. A. Stankiewicz, J. Sagerer, E. García, Jaw-Luen Tang, C. E. Smith, Inkyu Park, P. Sarin, A. Budzanowski, and M. P. Decowski

Subjects
Physics, Nuclear physics, Nuclear and High Energy Physics, Pseudorapidity, Astronomy and Astrophysics, Multiplicity (mathematics), Limiting, Atomic physics, Nuclear Experiment, Scaling, Atomic and Molecular Physics, and Optics, Charged particle
Abstract

In this talk I will review PHOBOS data on charged particle multiplicities, obtained in Au + Au and d + Au collisions at RHIC. The general features of the Au + Au pseudorapidity distributions results will be discussed and compared to those of [Formula: see text] collisions. The total charged particle multiplicity, scaled by the number of participant pairs, is observed to be about 40% higher in Au + Au collisions than in [Formula: see text] and d + Au systems, but, surprisingly at the same level of e+e- collisions. Limiting fragmentation scaling is seen to be obeyed in Au + Au collisions.

Published
2005

6. Elliptic flow in Au+Au collisions at RHIC

Author

Carla M Vale, B B Back, M D Baker, M Ballintijn, D S Barton, R R Betts, A A Bickley, R Bindel, A Budzanowski, W Busza, A Carroll, M P Decowski, E García, N George, K Gulbrandsen, S Gushue, C Halliwell, J Hamblen, G A Heintzelman, C Henderson, D J Hofman, R S Hollis, R Hołyński, B Holzman, A Iordanova, E Johnson, J L Kane, J Katzy, N Khan, W Kucewicz, P Kulinich, C M Kuo, W T Lin, S Manly, D McLeod, A C Mignerey, M Ngyuen, R Nouicer, A Olszewski, R Pak, I C Park, H Pernegger, C Reed, L P Remsberg, M Reuter, C Roland, G Roland, L Rosenberg, J Sagerer, P Sarin, P Sawicki, W Skulski, P Steinberg, G S F Stephans, A Sukhanov, J-L Tang, M B Tonjes, A Trzupek, G J van Nieuwenhuizen, R Verdier, G Veres, F L H Wolfs, B Wosiek, K Woźniak, A H Wuosmaa, and B Wysłouch

Subjects
Physics, Nuclear and High Energy Physics, Range (particle radiation), 010308 nuclear & particles physics, Detector, Elliptic flow, FOS: Physical sciences, 01 natural sciences, 7. Clean energy, Charged particle, Nuclear physics, Azimuth, Pseudorapidity, 0103 physical sciences, High Energy Physics::Experiment, Nuclear Experiment (nucl-ex), Nuclear Experiment, 010306 general physics, Anisotropy, Relativistic Heavy Ion Collider
Abstract

Elliptic flow is an interesting probe of the dynamical evolution of the dense system formed in the ultrarelativistic heavy ion collisions at the Relativistic Heavy Ion Collider (RHIC). The elliptic flow dependences on transverse momentum, centrality, and pseudorapidity were measured using data collected by the PHOBOS detector, which offers a unique opportunity to study the azimuthal anisotropies of charged particles over a wide range of pseudorapidity. These measurements are presented, together with an overview of the analysis methods and a discussion of the results., Comment: Presented at Hot Quarks 2004; 7 pages, 6 figures

Published
2005

7. Recent results from PHOBOS at RHIC

Author

Andrzej Olszewski, Russell Richard Betts, Conor Henderson, L.J. Rosenberg, F. L. H. Wolfs, J. Sagerer, Bruce Becker, J.W. Lee, Baker, Jaw-Luen Tang, T. Gburek, Krzysztof Wozniak, D. McLeod, Barbara Wosiek, Burt Holzman, A. S. Carroll, R. Verdier, A. H. Wuosmaa, N. George, Marguerite Tonjes, C. E. Smith, P. Kulinich, W. Skulski, George Stephans, W. Kucewicz, J. L. Kane, B. Wysouch, C. Reed, S. Gushue, David Jonathan Hofman, S. Manly, C. Halliwell, M. Reuter, E. García, Jian Zhang, G. A. Heintzelman, P. Sarin, A. S. Harrington, C. Vale, Heinz Pernegger, K. Gulbrandsen, Christof Roland, Chia-Ming Kuo, P. Sawicki, Rachid Nouicer, Adam Trzupek, A. Sukhanov, L. P. Remsberg, J. Katzy, I. Sedykh, M. Ballintijn, Alice Mignerey, R. Hoynski, A. Iordanova, G. Van Nieuwenhuizen, Wit Busza, R. S. Hollis, J. Hamblen, R. Bindel, B. B. Back, Willis Lin, M. P. Decowski, A. Budzanowski, Inkyu Park, N. Khan, R. Pak, D. S. Barton, A. A. Bickley, Gunther Roland, Gabor Istvan Veres, Peter Steinberg, and E. Johnson

Subjects
Physics, Particle physics, Hadron, General Physics and Astronomy, Spectral line, Nuclear physics, Pseudorapidity, Transverse momentum, High Energy Physics::Experiment, Multiplicity (chemistry), Nuclear Experiment, Relativistic Heavy Ion Collider, Scaling, Multiplicity distribution
Abstract

PHOBOS is one of the four heavy ion experiments currently running at the Relativistic Heavy Ion Collider (RHIC). In this paper we will present some of the current results from PHOBOS: the study of charged multiplicity distribution as function of pseudorapidity and centrality at = 19.6, 130 and 200 GeV, a discussion of multiplicity scaling, and a measurement of transverse momentum spectra (pT) of charged hadrons produced in d+Au and Au+Au interactions at = 200 GeV. The dependence of the Au+Au yields as function of centrality is found to be independent of pT. A strong suppression in the Au+Au hadron spectra relative to p at high pT is observed. The spectral shape for d+Au collisions is significantly different from the observations in Au+Au, the yield suppression is not observed in d+Au.

Published
2004

8. Charged particle multiplicity fluctuations in Au+Au collisions at

Author

Krzysztof Wozniak, Barbara Wosiek, A. Sukhanov, P. Sarin, Wit Busza, R. Pak, Alice Mignerey, N. George, Peter Steinberg, R. Bindel, W. Skulski, Burt Holzman, R. S. Hollis, E. Johnson, P. Sawicki, Gunther Roland, Z. Chai, Russell Richard Betts, R. Holynski, B. B. Back, Conor Henderson, Inkyu Park, D. McLeod, J. Sagerer, George Stephans, Bolek Wyslouch, Jaw-Luen Tang, Christof Roland, A. H. Wuosmaa, D. S. Barton, C. Reed, M. P. Decowski, F. L. H. Wolfs, W. Kucewicz, A. A. Bickley, Chia-Ming Kuo, L. P. Remsberg, J. L. Kane, L.J. Rosenberg, M. Reuter, David Jonathan Hofman, G. Van Nieuwenhuizen, S. Manly, Rachid Nouicer, Adam Trzupek, M. Ballintijn, M. D. Baker, K. Gulbrandsen, W. T. Lin, J. Hamblen, C. Vale, Heinz Pernegger, A. S. Carroll, Andrzej Olszewski, R. Verdier, A. Iordanova, E. García, C. Halliwell, N. Khan, S. Gushue, J. Katzy, A. Budzanowski, G. A. Heintzelman, and P. Kulinich

Subjects
Nuclear physics, Physics, Nuclear and High Energy Physics, Particle physics, Range (particle radiation), Particle number, Pseudorapidity, Multiplicity (mathematics), Nuclear Experiment, Collision, Charged particle
Abstract

This paper presents the first PHOBOS results on charged particle multiplicity fluctuations measured for Au+Au collisions at the highest RHIC energy within a wide pseudorapidity range of |η| < 3. The dependence on collision geometry is removed in the analysis by using the normalized difference between the number of particles in separate η bins. We compare our data to HIJING model predictions.

Published
2004

9. Identified hadron spectra from PHOBOS

Author

P. Sarin, Andrzej Olszewski, Russell Richard Betts, R. Pak, W. Skulski, Conor Henderson, I. Sedykh, P. Kulinich, T. Gburek, Krzysztof Wozniak, Burt Holzman, A. Sukhanov, A. S. Carroll, R. Verdier, George Stephans, Barbara Wosiek, S. Gushue, A. S. Harrington, C. Halliwell, Wit Busza, Chia-Ming Kuo, G. Van Nieuwenhuizen, Christof Roland, A. Iordanova, J. L. Kane, M. P. Decowski, F. L. H. Wolfs, K. Gulbrandsen, S. Manly, R. Holynski, M. D. Baker, M. Ballintijn, J. Sagerer, J.W. Lee, R. S. Hollis, Rachid Nouicer, Adam Trzupek, J. Hamblen, Bolek Wyslouch, David Jonathan Hofman, Gabor Istvan Veres, Jian Zhang, Peter Steinberg, Alice Mignerey, R. Bindel, E. Johnson, C. E. Smith, E. García, C. Vale, Heinz Pernegger, Marguerite Tonjes, Gunther Roland, C. Reed, B. B. Back, Bruce Becker, Willis Lin, N. Khan, D. S. Barton, A. A. Bickley, Inkyu Park, and N. George

Subjects
Physics, Nuclear and High Energy Physics, Antiparticle, Particle physics, Range (particle radiation), Nuclear Theory, Hadron, Spectral line, Particle identification, Nuclear physics, Pion, Pseudorapidity, Particle, High Energy Physics::Experiment, Nuclear Experiment
Abstract

Transverse momentum spectra of pions, kaons and protons, as well as antiparticle to particle ratios near mid-rapidity from d+Au collisions at √S NN = 200 GeV have been measured by the PHOBOS experiment at RHIC. The transverse momentum range of particle identification was extended to beyond 3 GeV/c using the TOF detector and a new trigger system. The pseudorapidity dependence of the nuclear modification factor for charged hadrons in d+Au collisions is presented.

Published
2004

10. Pseudorapidity distributions of charged particles in d+Au and p+p collisions at

Author

Gunther Roland, Alice Mignerey, C. Halliwell, George Stephans, A. S. Harrington, I. Sedykh, S Manly, R. Bindel, Andrzej Olszewski, Krzysztof Wozniak, A. Iordanova, G. Van Nieuwenhuizen, Barbara Wosiek, J. L. Kane, J. Sagerer, F. L. H. Wolfs, K. Gulbrandsen, R. S. Hollis, Marguerite Tonjes, M. P. Decowski, W. Skulski, C. Reed, Burt Holzman, A. S. Carroll, B. B. Back, David Jonathan Hofman, P. Sarin, W T Lin, R. Verdier, T. Gburek, Bruce Becker, J. Zhang, R. Holynski, J W Lee, P. Kulinich, A. Sukhanov, C. Vale, Heinz Pernegger, M. D. Baker, Wit Busza, R. Pak, Chia-Ming Kuo, D. S. Barton, A. A. Bickley, M. Ballintijn, J. Hamblen, E. García, C. E. Smith, Christof Roland, S. Gushue, Bolek Wyslouch, N. Khan, Inkyu Park, N. George, Russell Richard Betts, Conor Henderson, Rachid Nouicer, Adam Trzupek, Gabor Istvan Veres, Peter Steinberg, and E. Johnson

Subjects
Physics, Nuclear and High Energy Physics, Range (particle radiation), Proton, 010308 nuclear & particles physics, Inelastic collision, Multiplicity (mathematics), 01 natural sciences, Charged particle, Nuclear physics, Deuterium, Fragmentation (mass spectrometry), Pseudorapidity, 0103 physical sciences, Nuclear Experiment, 010306 general physics
Abstract

The measured pseudorapidity distributions of primary charged particles are presented for d+Au and p+p collisions at √S NN = 200 GeV over a wide pseudorapidity range of |η| ≤ 5.4. The results for d+Au collisions are presented for minimum-bias events and as a function of collision centrality. The measurements for p+p collisions are shown for minimum-bias events. The ratio of the charged particle multiplicity in d+Au and p+A collisions relative to that for inelastic p+p collisions is found to depend only on , and it is remarkably independent of collision energy and system mass. The deuteron and gold fragmentation regions in d+Au collisions are in good agreement with proton nucleus data at lower energies.

Published
2004

11. Results from the PHOBOS experiment at RHIC

Author

D. McLeod, K. Gulbrandsen, A. S. Carroll, R. Verdier, J. Katzy, A. Sukhanov, M. P. Decowski, P. Kulinich, W. Kucewicz, Wit Busza, C. Halliwell, F. L. H. Wolfs, Rachid Nouicer, Adam Trzupek, W. T. Lin, Andrzej Olszewski, R. Pak, Baker, Chia-Ming Kuo, P. Sawicki, Inkyu Park, David Jonathan Hofman, J.W. Lee, N. George, Barbara Wosiek, W. Skulski, Burt Holzman, Gunther Roland, J. Sagerer, R. S. Hollis, A. Budzanowski, P. Sarin, I. Sedykh, Christof Roland, Russell Richard Betts, Conor Henderson, A. H. Wuosmaa, C. Vale, Heinz Pernegger, M. Reuter, Jian Zhang, N. Khan, Marguerite Tonjes, E. Garcia, G. Van Nieuwenhuizen, M. Ballintijn, K. Wozniak, C. Reed, L. P. Remsberg, Alice Mignerey, J. Hamblen, R. Bindel, R. Holynski, A. S. Harrington, A. Iordanova, D. S. Barton, A. A. Bickley, C. E. Smith, Bolek Wyslouch, L.J. Rosenberg, T. Gburek, S. Gushue, G. A. Heintzelman, J. L. Kane, S. Manly, B. B. Back, J.L. Teng, Gabor Istvan Veres, Peter Steinberg, E. Johnson, G.S.F. Stephans, and Bruce Becker

Subjects
Physics, Nuclear reaction, Nuclear and High Energy Physics, Spectrometer, Physics::Instrumentation and Detectors, Elliptic flow, Particle accelerator, Particle detector, law.invention, Semiconductor detector, Nuclear physics, law, High Energy Physics::Experiment, Atomic physics, Multiplicity (chemistry), Nuclear Experiment, Relativistic Heavy Ion Collider
Abstract

PHOBOS is one of the four experiments at the Relativistic Heavy Ion Collider measuring p + p, d + Au , and Au + Au collisions over a broad range of energies. PHOBOS is a silicon-pad based detector with a 4π multiplicity detector and a high resolution mid-rapidity spectrometer, along with other detectors (time-of-flight walls, proton and zero degree calorimeters). PHOBOS is able to measure particles at low transverse momentum, spectra, flow, particle ratios, and multiplicity over a large region of phase space. A comparison of results for Au + Au and d + Au collisions at √S NN = 220GeV will be discussed.

Published
2004

12. Strange hadron production at low transverse momenta

Author

A. S. Carroll, R. Verdier, A. S. Harrington, P. Kulinich, Chia-Ming Kuo, C. Halliwell, Inkyu Park, Marguerite Tonjes, A. H. Wuosmaa, B.F. Wadsworth, B. B. Back, Barbara Wosiek, Bolek Wyslouch, Gunther Roland, A. Noell, Christof Roland, M. Ballintijn, A. Iordanova, R. Teng, Andrzej Olszewski, J. Hamblen, C. Reed, C. E. Smith, Alice Mignerey, A. Budzanowski, P. Sarin, R. Bindel, Rachid Nouicer, Adam Trzupek, J. L. Kane, S. Manly, M. P. Decowski, L. P. Remsberg, Bruce Becker, F. L. H. Wolfs, K. Gulbrandsen, R. S. Hollis, David Jonathan Hofman, E. García, N. Khan, J. Sagerer, R. Holynski, Russell Richard Betts, Conor Henderson, M. D. Baker, T. Gburek, S. Gushue, C. Vale, Heinz Pernegger, Gabor Istvan Veres, Peter Steinberg, R. Pak, E. Johnson, W. T. Lin, D. S. Barton, A. A. Bickley, I. Sedykh, A. Sukhanov, G. Van Nieuwenhuizen, J.W. Lee, Wit Busza, N. George, W. Skulski, Burt Holzman, Jian Zhang, George Stephans, Krzysztof Woźniak, and P. Sawicki

Subjects
Physics, Nuclear and High Energy Physics, Particle physics, Nuclear Theory, Hadron, Strangeness production, Strangeness, Collision, Ion, Nuclear physics, Baryon, Transverse plane, Nuclear Experiment, Nucleon
Abstract

Some of the latest results of the PHOBOS experiment from the √s NN = 200 GeV Au+Au data are discussed. Those relevant to strangeness production are emphasized. These observations relate to the nature of the matter created when heavy ions collide at the highest achieved energy. The invariant yields of strange and non-strange charged hadrons at very low transverse momentum have been measured, and used to differentiate between different dynamical scenarios. In the intermediate transverse momentum range, the measured ratios of strange and anti-strange kaons approach one, while the antibaryon to baryon ratio is still significantly less, independent of collision centrality and transverse momentum. At high transverse momenta, we find that central and peripheral Au+Au collisions produce similar numbers of charged hadrons per participant nucleon pair, rather than per binary nucleon-nucleon collision.

Published
2003

13. PHOBOS at RHIC: Some global observations

Author

Alice Mignerey, G. Van Nieuwenhuizen, A. Budzanowski, S. Gushue, F. L. H. Wolfs, R. Teng, R. Bindel, P. Sawicki, W. T. Lin, J. Michałowski, C. Halliwell, E. García, L. P. Remsberg, Andrzej Olszewski, G. A. Heintzelman, P. Sarin, B.F. Wadsworth, S. G. Steadman, K. Woźniak, P. Kulinich, A. H. Wuosmaa, M. P. Decowski, W. Skulski, Gunther Roland, Burt Holzman, A. S. Carroll, R. Verdier, D. McLeod, Christof Roland, Bolek Wyslouch, P. Steinberg, M. Reuter, R. S. Hollis, M. D. Baker, L.J. Rosenberg, C. Reed, A. Iordanova, B. B. Back, R. Pak, R. Holynski, Chia-Ming Kuo, Barbara Wosiek, M. Stodulski, J. L. Kane, David Jonathan Hofman, S. Manly, J. Sagerer, C. Vale, Heinz Pernegger, M. Ballintijn, Jaw-Luen Tang, K. Gulbrandsen, J. Hamblen, J. Katzy, E. Johnson, Russell Richard Betts, Conor Henderson, Rachid Nouicer, Adam Trzupek, Inkyu Park, N. George, W. Kucewicz, A. Sukhanov, Wit Busza, N. Khan, George Stephans, D. S. Barton, and A. A. Bickley

Subjects
Physics, Nuclear physics, Particle physics, General Physics and Astronomy, High Energy Physics::Experiment, Heavy ion, Multiplicity (chemistry), Nuclear Experiment, Scaling
Abstract

Particle production in Au+Au collisions has been measured in the PHOBOS experiment at RHIC for a range of collision energies for a large span of pseudorapidities, |η| 65. This scaling occurs both for the total multiplicity and for highp T particles (3

Published
2003

14. Identified particles in Au+Au collisions at GeV

Author

Barbara Wosiek, B.B. Back, M.D. Baker, D.S. Barton, R.R. Betts, M. Ballintijn, A.A. Bickley, R. Bindel, A. Budzanowski, W. Busza, A. Carroll, M.P. Decowski, E. García, N. George, K. Gulbrandsen, S. Gushue, C. Halliwell, J. Hamblen, G.A. Heintzelman, C. Henderson, D.J. Hofman, R.S. Hollis, R. Hołyński, B. Holzman, A. Iordanova, E. Johnson, J.L. Kane, J. Katzy, N. Khan, W. Kucewicz, P. Kulinich, C.M. Kuo, S. Manly, D. McLeod, J. Michałowski, A.C. Mignerey, R. Nouicer, A. Olszewski, R. Pak, I.C. Park, H. Pernegger, C. Reed, L.P. Remsberg, M. Reuter, C. Roland, G. Roland, L. Rosenberg, J. Sagerer, P. Sarin, P. Sawicki, W. Skulski, S.G. Steadman, P. Steinberg, G.S.F. Stephans, M. Stodulski, A. Sukhanov, J.-L. Tang, R. Teng, A. Trzupek, C. Vale, G.J. van Nieuwenhuizen, R. Verdier, B. Wadsworth, F.L.H. Wolfs, B. Wosiek, K. Woźniak, A.H. Wuosmaa, and B. Wysłouch

Subjects
Physics, Nuclear and High Energy Physics, Antiparticle, Spectrometer, 010308 nuclear & particles physics, Nuclear Theory, Invariant (physics), 7. Clean energy, 01 natural sciences, Nuclear physics, Transverse plane, Pion, 0103 physical sciences, High Energy Physics::Experiment, Nuclear Experiment, 010306 general physics
Abstract

The yields of identified particles have been measured at RHIC for Au+Au collisions at sqrt{s_NN} = 200 GeV using the PHOBOS spectrometer. The ratios of antiparticle to particle yields near mid-rapidity are presented. The first measurements of the invariant yields of charged pions, kaons and protons at very low transverse momenta are also shown.

Published
2003

15. Charged hadron transverse momentum distributions in Au+Au collisions at GeV

Author

B.B. Back, M.D. Baker, D.S. Barton, R.R. Betts, M. Ballintijn, A.A. Bickley, R. Bindel, A. Budzanowski, W. Busza, A. Carroll, M.P. Decowski, E. García, N. George, K. Gulbrandsen, S. Gushue, C. Halliwell, J. Hamblen, G.A. Heintzelman, C. Henderson, D.J. Hofman, R.S. Hollis, R. Hołyński, B. Holzman, A. Iordanova, E. Johnson, J.L. Kane, J. Katzy, N. Khan, W. Kucewicz, P. Kulinich, C.M. Kuo, W.T. Lin, S. Manly, D. McLeod, J. Michałowski, A.C. Mignerey, R. Nouicer, A. Olszewski, R. Pak, I.C. Park, H. Pernegger, C. Reed, L.P. Remsberg, M. Reuter, C. Roland, G. Roland, L. Rosenberg, J. Sagerer, P. Sarin, P. Sawicki, W. Skulski, S.G. Steadman, P. Steinberg, G.S.F. Stephans, M. Stodulski, A. Sukhanov, J.-L. Tang, R. Teng, A. Trzupek, C. Vale, G.J. van Nieuwenhuizen, R. Verdier, B. Wadsworth, F.L.H. Wolfs, B. Wosiek, K. Woźniak, A.H. Wuosmaa, and B. Wysłouch

Subjects
Physics, Nuclear and High Energy Physics, Particle physics, Range (particle radiation), 010308 nuclear & particles physics, Nuclear Theory, Hadron, Binary number, 01 natural sciences, Spectral line, Transverse plane, 0103 physical sciences, Transverse momentum, High Energy Physics::Experiment, Nuclear Experiment, 010306 general physics, Nucleon, Scaling
Abstract

We present transverse momentum distributions of charged hadrons produced in Au+Au collisions at sqrt(s_NN) = 200 GeV. The evolution of the spectra for transverse momenta p_T from 0.25 to 5GeV/c is studied as a function of collision centrality over a range from 65 to 344 participating nucleons. We find a significant change of the spectral shape between proton-antiproton and peripheral Au+Au collisions. Comparing peripheral to central Au+Au collisions, we find that the yields at the highest p_T exhibit approximate scaling with the number of participating nucleons, rather than scaling with the number of binary collisions.

Published
2003

16. The PHOBOS detector at RHIC

Author

L. P. Remsberg, W. Czyz, A. Sukhanov, B. B. Back, P. Kulinich, Christof Roland, Barbara Wosiek, Willis Lin, A. Budzanowski, J. Michałowski, G. Van Nieuwenhuizen, Alice Mignerey, Krzysztof Woźniak, H.W. Kraner, R. Bindel, Andrzej Olszewski, R. Pak, A. Bialas, J. Fitch, W. Bogucki, J. L. Kane, P. Haridas, C. Halliwell, A. Sanzgiri, S. Manly, M. P. Decowski, R. Teng, M. Friedl, T. Coghen, Burt Holzman, Marek Stodulski, John P. Ryan, Rachid Nouicer, Adam Trzupek, J. Sinacore, Boleslaw Wyslouch, B.F. Wadsworth, C. Reed, K. Gulbrandsen, R. Baum, C Connor, Jan Godlewski, N. George, Yuan-Hann Chang, David Jonathan Hofman, E. Garcia, K. Zalewski, Russell Richard Betts, Conor Henderson, C. Gomes, M. Neal, D. Ross, P. Sawicki, F.L.H. Wolfs, W. Skulski, P. Żychowski, A. H. Wuosmaa, A. B. Hayes, P. Fita, C. Vale, Heinz Pernegger, J. Halik, W. Kucewicz, Peter Steinberg, K. Surowiecka, A. Straczek, S. G. Steadman, J. Katzy, A. E. Chen, Pankaj Sarin, M. Ceglia, Gunther Roland, D. McLeod, E. Johnson, E. Griesmayer, Wit Busza, M. Reuter, A. S. Carroll, R. Verdier, M. D. Baker, M. Patel, D. S. Barton, R. S. Hollis, Z. Stopa, J. Scaduto, Bogdan Dabrowski, W. Kita, S. Gushue, J. Shea, G. S. F. Stephans, Johannes Mülmenstädt, M. Lemler, Jaw-Luen Tang, G. A. Heintzelman, M. Despet, K. Gałuszka, C. Law, R. Holynski, J. Kotula, L.J. Rosenberg, R. Ganz, M. Strȩk, Inkyu Park, S. Basilev, J. Ligocki, and M. Plesko

Subjects
Physics, Nuclear and High Energy Physics, Spectrometer, Physics::Instrumentation and Detectors, Cherenkov detector, Detector, Scintillator, Charged particle, Particle identification, Particle detector, Semiconductor detector, law.invention, Nuclear physics, law, Nuclear Experiment, Instrumentation
Abstract

This manuscript contains a detailed description of the PHOBOS experiment as it is configured for the Year 2001 running period. It is capable of detecting charged particles over the full solid angle using a multiplicity detector and measuring identified charged particles near mid-rapidity in two spectrometer arms with opposite magnetic fields. Both of these components utilize silicon pad detectors for charged particle detection. The minimization of material between the collision vertex and the first layers of silicon detectors allows for the detection of charged particles with very low transverse momenta, which is a unique feature of the PHOBOS experiment. Additional detectors include a time-of-flight wall which extends the particle identification range for one spectrometer arm, as well as sets of scintillator paddle and Cherenkov detector arrays for event triggering and centrality selection.

Published
2003

17. Overview of results from PHOBOS experiment at RHIC

Author

Andrzej Olszewski, Rachid Nouicer, Adam Trzupek, Barbara Wosiek, J. Michałowski, A. Budzanowski, F. L. H. Wolfs, C. Reed, C. Halliwell, Alice Mignerey, R. S. Hollis, N. Khan, Chia-Ming Kuo, George Stephans, B. Wadsworth, R. Bindel, D. S. Barton, K. Woźniak, D. Hicks, M. Reuter, M. D. Baker, M. Rafelski, P. Sawicki, K. Gulbrandsen, J. Hamblen, S. G. Steadman, R. Teng, W. Kucewicz, A. S. Carroll, W. T. Lin, M. Stodulski, R. Verdier, Russell Richard Betts, Conor Henderson, David Jonathan Hofman, M. P. Decowski, J. Katzy, J. Sagerer, Johannes Mülmenstädt, A. H. Wuosmaa, D. McLeod, Jaw-Luen Tang, A. Iordanova, J. L. Kane, C. Vale, Heinz Pernegger, M. Rbeiz, R. Pak, G. Van Nieuwenhuizen, Peter Steinberg, P. Kulinich, S. Manly, R. Holynski, J. Corbo, E. Johnson, Wit Busza, Gunther Roland, N. George, B. B. Back, W. Skulski, Burt Holzman, P. Sarin, Inkyu Park, E. Garcia, L. P. Remsberg, A. Sukhanov, Christof Roland, Bolek Wyslouch, L.J. Rosenberg, A. Oiszewski, and S. Gushue

Subjects
Physics, Nuclear physics, Nuclear and High Energy Physics, Particle physics, Pion, Elliptic flow, Particle, Particle flow, Nuclear Experiment, Nucleon, Collision, Charged particle, Ion
Abstract

An overview of results for interactions of Au+Au ions at centre-of-mass energies of √sNN = 56, 130 and 200 GeV obtained by the PHOBOS collaboration at RHIC is given. Measurements of primary charged particle density near mid-rapidity indicate that particle production grows logarithmically with collision energy and faster than linearly with the number of interacting nucleons. Elliptic flow is found to be much stronger at RHIC than at SPS energy. The effect is strongest in peripheral events and decreases for more central collisions and emission angles |η| > 1. The measured anti-particle to particle ratios of production rates for pions, kaons and protons in central Au+Au interactions at √sNN = 130 GeV are compatible with the statistical model of particle production, showing an increasingly baryon-free region in mid-rapidity with the increase of collision energy.

Published
2002

18. Neutral strange particle dynamics in Au $plus$ Au collisions at AGS energies

Author

P Chung for the E895 Collaboration, J M Alexander, N N Ajitanand, M Anderson, D Best, F P Brady, T Case, W Caskey, D Cebra, J L Chance, P Chung, B Cole, K Crowe, A C Das, J E Draper, M L Gilkes, S Gushue, M Heffner, A S Hirsch, E L Hjort, L Huo, M Justice, M Kaplan, D Keane, J C Kintner, J Klay, D Krofcheck, Roy A Lacey, J Lauret, M A Lisa, H Liu, Y M Liu, R McGrath, Z Milosevich, G Odyniec, D L Olson, S Panitkin, C Pinkenburg, N T Porile, G Rai, H G Ritter, J L Romero, R Scharenberg, L Schroeder, B Srivastava, N T B Stone, T J M Symons, J Whitfield, T Wienold, R Witt, L Wood, and W N Zhang

Subjects
Physics, Nuclear and High Energy Physics, Strange quark, Space time, Gaussian, Dynamics (mechanics), Magnitude (mathematics), Scattering length, Radius, Nuclear physics, symbols.namesake, Pion, symbols, High Energy Physics::Experiment, Atomic physics, Nuclear Experiment
Abstract

The E895 Collaboration has investigated a number of mixed-particle correlations involving neutral strange particles (K0s and Λ) in 2, 4, 6 and 8 A GeV Au + Au collisions at the AGS. The first measurements for pΛ correlations indicate a correlation magnitude of about 50% with a 26 MeV width. Detailed comparisons between data and theory suggest an emitting source with an effective Gaussian radius close to 4.5 fm. This radius is much larger than the value of 2.8 fm predicted by the relativistic transport code ART. Pairs of pK0, π−Λ and π−K0 are found to display essentially zero correlation at 6 A GeV. The latter observations are not unexpected considering that the proton–K0 interaction has a very small scattering length and there are no very well known interactions between pions and Λs or K0s.

Published
2002

19. Results from the PHOBOS Experiment at RHIC

Author

Alice Mignerey, R. Bindel, Andrzej Olszewski, N. George, W. Skulski, Burt Holzman, M. P. Decowski, P. Sarin, Inkyu Park, P. Kulinich, W. Kucewicz, Rachid Nouicer, Adam Trzupek, Christof Roland, J. Michałowski, C. Halliwell, C. Reed, David Jonathan Hofman, R. Pak, D. McLeod, B.F. Wadsworth, Marek Stodulski, D. S. Barton, S. G. Steadman, Krzysztof Woźniak, N. Khan, A. H. Wuosmaa, George Stephans, C. Vale, Heinz Pernegger, M. Reuter, F. L. H. Wolfs, Gunther Roland, R. Teng, A. Budzanowski, Peter Steinberg, M. D. Baker, A. Sukhanov, W. T. Lin, B. B. Back, Johannes Mülmenstädt, Wit Busza, E. Garcia, E. Johnson, K. Gulbrandsen, Jaw-Luen Tang, G. Van Nieuwenhuizen, J. Katzy, A. S. Carroll, R. Verdier, R. Holynski, J. L. Kane, S. Manly, P. Sawicki, Russell Richard Betts, Conor Henderson, Bolek Wyslouch, L.J. Rosenberg, Barbara Wosiek, S. Gushue, G. A. Heintzelman, and L. P. Remsberg

Subjects
Physics, Nuclear and High Energy Physics, Particle physics, Range (particle radiation), Elliptic flow, Hadron, General Physics and Astronomy, Charged particle, Nuclear physics, Antiproton, High Energy Physics::Experiment, Nuclear Experiment, Energy (signal processing), Bar (unit)
Abstract

Au+Au collisions have been studied at center-of-mass energies of $$\sqrt {s_{NN} } = 56$$ and 130 GeV using the PHOBOS detector at RHIC. Charged particle multiplicites have been measured as a function of center-of-mass energy, centrality and pseudo-rapidity, η. A total of 4100±400 charged particles are observed in the pseudo-rapidity range −5.4 < η < 5.4 for the most central collisions. A strong elliptic flow signal is seen in peripheral collisions at η = 0. The measurement of an antiprotons to protons ratio of $$\bar p/p = 0.60 \pm 0.04(stat) \pm 0.06(syst)$$ indicates that a nearly baryon-free region is created at midrapidity.

Published
2002

20. First performance results of the Phobos silicon detectors

Author

S. G. Steadman, Andrzej Olszewski, Alice Mignerey, R. Bindel, Burt Holzman, L. P. Remsberg, Inkyu Park, N. Khan, Barbara Wosiek, K. Gulbrandsen, N. George, George Stephans, A. Budzanowski, P. Sarin, P. Sawicki, W. Skulski, David Jonathan Hofman, S. Gushue, W. Kucewicz, F. L. H. Wolfs, A. H. Wuosmaa, J. Katzy, G. A. Heintzelman, W. T. Lin, M. P. Decowski, C. Vale, Heinz Pernegger, Johannes Mülmenstädt, Marek Stodulski, P. Kulinich, Wit Busza, Jaw-Luen Tang, Bolek Wyslouch, R. Holynski, D. McLeod, Peter Steinberg, L.J. Rosenberg, Krzysztof Woźniak, A. Sukhanov, G. Van Nieuwenhuizen, E. Johnson, J. L. Kane, C. Reed, A. S. Carroll, R. Verdier, E. Garcia, S. Manly, J. Michałowski, C. Halliwell, B.F. Wadsworth, J. Hamblen, B. B. Back, R. Pak, Gunther Roland, M. Reuter, M. D. Baker, Christof Roland, D. S. Barton, R. Teng, Rachid Nouicer, Adam Trzupek, Russell Richard Betts, and Conor Henderson

Subjects
Physics, Nuclear and High Energy Physics, Signal response, Silicon, Physics::Instrumentation and Detectors, Detector, chemistry.chemical_element, Solid state detector, Performance results, Nuclear physics, chemistry, Multiplicity (chemistry), Nuclear Experiment, Nucleon, Instrumentation, Channel occupancy
Abstract

The Phobos experiment concluded its first year of operation at RHIC taking data in Au–Au nucleus collisions at s nn =65 GeV and 130 GeV / nucleon pair. First preliminary results of the performances of our silicon detectors in the experiment are summarized. The Phobos experiment uses silicon pad detectors for both tracking and multiplicity measurements. The silicon sensors vary strongly in their pad geometry. In this paper, we compare the signal response, the signal uniformity and signal-to-noise performance as measured in the experiment for the different geometries. Additionally, we investigate effects of very high channel occupancy on the signal response.

Published
2001

21. Directed Flow ofΛHyperons in(2–6)AGeVAu+AuCollisions

Author

M. A. Lisa, S. Y. Panitkin, N. T. B. Stone, H. G. Ritter, L. S. Schroeder, D. Best, David Krofcheck, E. Hjort, T. Wienold, T. Case, D. Keane, P. Chung, N. N. Ajitanand, G. Rai, J. L. Chance, Morton Kaplan, D. Cebra, F. P. Brady, G. Odyniec, S. Gushue, J. Whitfield, Y. M. Liu, Z. Milosevich, R. Witt, M. L. Gilkes, B. K. Srivastava, T. J. M. Symons, J. L. Romero, L. Wood, Brian Cole, Matthew J. Anderson, N. T. Porile, R. P. Scharenberg, J. Lauret, R. L. McGrath, J. M. Alexander, A. C. Das, H. Liu, J. L. Klay, Roy A. Lacey, M. Heffner, A. S. Hirsch, J. E. Draper, W. N. Zhang, M. Justice, Kenneth M. Crowe, D. L. Olson, W. Caskey, J. C. Kintner, Lei Huo, and C. Pinkenburg

Subjects
Nuclear reaction, Physics, Nuclear Theory, Hadron, Hyperon, General Physics and Astronomy, Elementary particle, Lambda baryon, Lambda, Baryon, Nuclear physics, Atomic physics, Nuclear Experiment, Nucleon
Abstract

Directed flow measurements for {Lambda} hyperons are presented and compared to those for protons produced in the same Au+Au collisions (2A, 4A, and 6AGeV; b

Published
2001

22. Λ flow and Λ-P correlation in Au + Au collisions at AGS energies

Author

C. Law, A. S. Hirsch, J. Whitfield, F. P. Brady, G. Odyniec, N. N. Ajitanand, J. E. Draper, K.M. Crowe, Lei Huo, W. N. Zhang, J. Lauret, N T B Stone, James Alexander, M. L. Gilkes, L. Wood, H. G. Ritter, Brian Cole, Matthew J. Anderson, J L Chance, M. Heffner, R. P. Scharenberg, A. C. Das, Y. M. Liu, H. Liu, Morton Kaplan, S. Y. Panitkin, Roy A. Lacey, C. Pinkenburg, S Gushue, T. J. M. Symons, E. L. Hjort, M. A. Lisa, M. Justice, D. Cebra, D. L. Olson, W. Caskey, Z. Milosevich, J. C. Kintner, R. Witt, L. S. Schroeder, B. K. Srivastava, D. Keane, P. Chung, G. Rai, T. Case, J. Klay, D. Best, J. L. Romero, David Krofcheck, N. T. Porile, and R. L. McGrath

Subjects
Quark, Physics, Nuclear and High Energy Physics, Scattering, Nuclear Theory, Hyperon, Magnitude (mathematics), Nuclear physics, Flow ratio, Transverse plane, Flow (mathematics), Atomic physics, Nuclear Experiment, Beam (structure)
Abstract

Transverse and radial flow measurements are presented for Λ hyperons along with Λ-P correlations from Au + Au collisions at AGS energies. The flow measurements are compared with those of co-produced protons. The measurements indicate that Λ hyperons flow consistently in the same direction as protons but with a smaller magnitude for all beam energies. Comparisons with RQMD calculations show that the experimentally determined Λ sideward flow is consistently larger compared with the calculated value obtained from scattering processes only. The experimental transverse flow ratio Λ/P is consistent with predictions ( 2/3) of the quark counting rule at 2 A GeV but is found to decrease with increasing beam energy. These observations may be related to the detailed features of the Λ-nucleon potential for the nuclear densities produced. At 6 A GeV, Λp correlation functions are observed to be essentially flat (within statistical uncertainty), indicating little or no correlation between Λs and co-produced protons. This suggests that Λs may have a spacetime emission pattern which is different from that for protons. Further evidence from radial flow measurements also indicates that 6 A GeV Λ hyperons (at mid-rapidity) do not share the same emitting source characteristics as co-produced protons.

Published
2001

23. How strange is PHOBOS? First RHIC physics results and future prospects

Author

L. P. Remsberg, S. G. Steadman, G. Van Nieuwenhuizen, M. Plesko, P. Sawicki, R. Verdier, Alice Mignerey, M. Strek, C. Halliwell, Christof Roland, F. L. H. Wolfs, R. Bindel, A. Białas, R. S. Hollis, J. Michałowski, W. T. Lin, A. E. Chen, J. Kotuła, J. Ligocki, P. Kulinich, Andrzej Olszewski, J. Ryan, A. Budzanowski, B.F. Wadsworth, A. Straczek, M. Despet, A. Sukhanov, C. Gomes, M. P. Decowski, D. Ross, R. Ganz, A. B. Hayes, Bolek Wyslouch, D. McLeod, E. Griesmayer, Jan Godlewski, H. Kraner, A. S. Carroll, Yuan-Hann Chang, D. S. Barton, M. Patel, J. Halik, Burt Holzman, P. Fita, C. Conner, Z. Stopa, K. Gulbrandsen, Barbara Wosiek, J. Fitch, A. Sanzgiri, C. Law, N. George, W. Skulski, A. H. Wuosmaa, B. B. Back, R. Baum, J. Scaduto, J. Katzy, P. Haridas, M. Neal, R. Holynski, K. Surowiecka, George Stephans, M. Ceglia, M. Friedl, Gunther Roland, B. D. Bates, K. Zalewski, L J Rosenberg, J. L. Kane, W. Czyz, R. Pak, S. Manly, Marek Stodulski, M. Reuter, Peter Steinberg, G. S. F. Stephans, Johannes Mülmenstädt, M. D. Baker, E. Johnson, P. Sarin, Jaw-Luen Tang, C. Reed, Bogdan Dabrowski, J. Shea, C. Vale, Heinz Pernegger, W. Kita, M. Lemler, E. Garcia, S. Gushue, S. Basilev, G. A. Heintzelman, K. Gałuszka, R. Teng, Inkyu Park, Wit Busza, P. Żychowski, T. Coghen, W. Kucewicz, Rachid Nouicer, Adam Trzupek, Krzysztof Woźniak, J. Sinacore, W. Bogucki, Russell Richard Betts, and Conor Henderson

Subjects
Physics, Nuclear physics, Nuclear and High Energy Physics, Particle physics, Pseudorapidity, Strangeness production, Nuclear Experiment, Nucleon, Charged particle, Beam (structure), Semiconductor detector, Rate of increase
Abstract

The early summer of 2000 saw the start of the RHIC experimental programme. The PHOBOS collaboration used data from the beginning of the running period to extract the first physics information about this exciting new regime. This first measurement consisted of pseudorapidity densities of primary charged particles near mid-rapidity in central Au + Au collisions at beam energies which gave centre-of-mass energies per pair of colliding nucleons of √snn = 56 and 130 GeV. The observed densities are higher than those observed previously in any collisions in the laboratory. In addition, the rate of increase in density between the two energies is significantly larger than that for nucleon-nucleon collisions at comparable beam energies. This paper will briefly describe the PHOBOS experiment (including the subset of the full detector installed for the early period of the RHIC beam), discuss the results of the first physics measurement and conclude with the prospects for the future, especially in the area of strangeness production.

Published
2001

24. Semi-inclusiveΛandKSProduction inp-Au Collisions at17.5GeV/c

Author

M. Moulson, Kenneth Francis Read, L. P. Remsberg, G. Rai, R. A. Soltz, Yanxi Zhang, R. L. McGrath, M. Rosati, Saskia Mioduszewski, D. Winter, H. Hiejima, A. D. Frawley, W. A. Zajc, M. L. Gilkes, S. P. Sorensen, M. N. Namboodiri, V. Cianciolo, Ju Hwan Kang, Y. Torun, Brian Cole, J. H. Thomas, E. P. Hartouni, S. Gushue, Richard C. Fernow, Yongcheol Shin, D. P. Morrison, N. Maeda, I. Chemakin, Xiaodong Yang, H.G. Kirk, and M. Justice

Subjects
Physics, Meson, 010308 nuclear & particles physics, Hadron, General Physics and Astronomy, Strangeness production, Multiplicity (mathematics), Strangeness, Lambda, Lambda baryon, 01 natural sciences, Nuclear physics, Baryon, 0103 physical sciences, Nuclear Experiment, 010306 general physics
Abstract

The first detailed measurements of the centrality dependence of strangeness production in p-A collisions are presented. {lambda} and K{sub S} dn/dy distributions from 17.5 GeV/c p-Au collisions are shown as a function of ''grey'' track multiplicity and the estimated number of collisions, {nu}, made by the proton. The {nu} dependence of the {Lambda} yield deviates from a scaling of p-p data by the number of participants, increasing faster than this scaling for {nu} {le} 5 and saturating for larger {nu}. A slower growth in K{sub S} multiplicity with {nu} is observed, consistent with a weaker {nu} dependence of KK-bar production than YK production.

Published
2000

25. Charged-Particle Multiplicity near Midrapidity in CentralAu+AuCollisions atsNN=56and130GeV

Author

Barbara Wosiek, H.W. Kraner, P. Haridas, L. P. Remsberg, P. Kulinich, B. D. Bates, R. Teng, M. Friedl, Alice Mignerey, S. Manly, J. Shea, Rachid Nouicer, Adam Trzupek, J. Sinacore, W. Czyz, C. Conner, Bolek Wyslouch, R. Bindel, W. T. Lin, A. Sanzgiri, P. Zychowski, L.J. Rosenberg, A. E. Chen, J. L. Kane, C. Law, M. Reuter, Jan Godlewski, Andrzej Olszewski, C. Gomes, A. Sukhanov, P. Sarin, M. D. Baker, J. Kotuła, K. Gulbrandsen, K. Zalewski, Russell Richard Betts, Conor Henderson, J. Fitch, F. L. H. Wolfs, Wit Busza, R. Pak, Christof Roland, J. Katzy, A. Straczek, J. Scaduto, P. Sawicki, S. Gushue, M. Neal, C. Vale, Heinz Pernegger, B. B. Back, J. Halik, G. Van Nieuwenhuizen, Bogdan Dabrowski, A. B. Hayes, R. S. Hollis, R. Holynski, M. Plesko, G. A. Heintzelman, M. P. Decowski, K. Gałuszka, W. Kucewicz, D. McLeod, W. Kita, E. Griesmayer, A. H. Wuosmaa, A. Białas, J. Ligocki, George Stephans, C. Reed, Krzysztof Woźniak, R. Ganz, W. Bogucki, M. Strȩk, R. Baum, A. Budzanowski, D. Ross, S. G. Steadman, Inkyu Park, T. Coghen, Yuan-Hann Chang, S. Basilev, Gunther Roland, Marek Stodulski, Peter Steinberg, P. Fita, E. Johnson, J. Michałowski, C. Halliwell, B.F. Wadsworth, Z. Stopa, A. S. Carroll, R. Verdier, M. Patel, D. S. Barton, Johannes Mülmenstädt, K. Surowiecka, Jaw-Luen Tang, E. Garcia, M. Despet, John P. Ryan, M. Ceglia, N. George, M. Lemler, W. Skulski, and Burt Holzman

Subjects
Physics, Particle physics, 010308 nuclear & particles physics, General Physics and Astronomy, 01 natural sciences, Central region, Charged particle, Nuclear physics, Pseudorapidity, 0103 physical sciences, High Energy Physics::Experiment, Rapidity, Multiplicity (chemistry), Nuclear Experiment, 010306 general physics
Abstract

We present the first measurement of pseudorapidity densities of primary charged particles near midrapidity in Au+Au collisions at sqrt[s(NN)] = 56 and 130 GeV. For the most central collisions, we find the charged-particle pseudorapidity density to be dN/deta|(|eta

Published
2000

26. Antiflow ofKs0Mesons in6AGeVAu+AuCollisions

Author

James Alexander, E. Hjort, A. S. Hirsch, T. Case, H. G. Ritter, F. P. Brady, G. Odyniec, J. L. Romero, N. T. Porile, M. A. Lisa, Kenneth M. Crowe, H. Liu, N. T. B. Stone, Brian Cole, Matthew J. Anderson, L. S. Schroeder, R. L. McGrath, R. P. Scharenberg, R. Witt, A. C. Das, W. N. Zhang, N. N. Ajitanand, B. K. Srivastava, J. Lauret, J. L. Klay, Roy A. Lacey, M. Justice, M. Heffner, Lei Huo, S. Gushue, M. L. Gilkes, J. Whitfield, T. Wienold, S. Y. Panitkin, C. Pinkenburg, Morton Kaplan, L. Wood, J. L. Chance, D. Cebra, J. E. Draper, Z. Milosevich, D. L. Olson, W. Caskey, Y. M. Liu, T. J. M. Symons, G. Rai, D. Keane, P. Chung, D. Best, David Krofcheck, and J. C. Kintner

Subjects
Nuclear reaction, Physics, Range (particle radiation), Meson, 010308 nuclear & particles physics, Hadron, General Physics and Astronomy, Elementary particle, Nuclear matter, 01 natural sciences, Nuclear physics, 0103 physical sciences, Impact parameter, 010306 general physics, Boson
Abstract

We have measured the sideward flow of neutral strange (K{sup 0}{sub s} ) mesons in 6A GeV Au +Au collisions. A prominent antiflow signal is observed for an impact parameter range (b(less-or-similar sign)7 fm ) which spans central and midcentral events. Since the K{sup 0}{sub s} scattering cross section is relatively small in nuclear matter, this observation suggests that the in-medium kaon vector potential plays an important role in high density nuclear matter. (c) 2000 The American Physical Society.

Published
2000

27. Sideward Flow inAu+AuCollisions between2Aand8AGeV

Author

H. Liu, N. N. Ajitanand, J. Alexander, M. Anderson, D. Best, F. P. Brady, T. Case, W. Caskey, D. Cebra, J. Chance, B. Cole, K. Crowe, A. Das, J. Draper, M. Gilkes, S. Gushue, M. Heffner, A. Hirsch, E. Hjort, L. Huo, M. Justice, M. Kaplan, D. Keane, J. Kintner, J. Klay, D. Krofcheck, R. Lacey, M. A. Lisa, Y. M. Liu, R. McGrath, Z. Milosevich, G. Odyniec, D. Olson, S. Y. Panitkin, N. Porile, G. Rai, H. G. Ritter, J. Romero, R. Scharenberg, L. S. Schroeder, B. Srivastava, N. T. B. Stone, T. J. M. Symons, S. Wang, J. Whitfield, T. Wienold, R. Witt, L. Wood, X. Yang, W. N. Zhang, and Y. Zhang

Subjects
Physics, Azimuth, Nuclear physics, Range (particle radiation), Time projection chamber, Flow (mathematics), Orientation (geometry), General Physics and Astronomy, Nuclear Experiment, Anisotropy, Fourier series, Beam (structure)
Abstract

Using the large acceptance Time Projection Chamber of experiment E895 at Brookhaven, measurements of collective sideward flow in Au+Au collisions at beam energies of 2A, 4A, 6A, and 8A GeV are presented in the form of in-plane transverse momentum and the first Fourier coefficient of azimuthal anisotropy v(1). These measurements indicate a smooth variation of sideward flow as a function of beam energy. The data are compared with four nuclear transport models which have an orientation towards this energy range. All four exhibit some qualitative trends similar to those found in the data, although none show a consistent pattern of agreement within experimental uncertainties.

Published
2000

28. Bombarding Energy Dependence ofπ−Interferometry at the Brookhaven AGS

Author

G. Odyniec, S. Gushue, E. Hjort, D. Best, T. Case, W. N. Zhang, T. J. M. Symons, J. L. Romero, H. G. Ritter, R. P. Scharenberg, David Krofcheck, Y. M. Liu, J. L. Chance, Kenneth M. Crowe, M. L. Gilkes, D. Cebra, A. C. Das, H. Liu, Brian Cole, Matthew J. Anderson, J. L. Klay, Roy A. Lacey, F. P. Brady, J. E. Draper, M. Heffner, J. Whitfield, D. Keane, P. Chung, A. S. Hirsch, J. Lauret, N. N. Ajitanand, M. A. Lisa, J. C. Kintner, G. Rai, S. Y. Panitkin, Russell Wells, J. M. Alexander, R. Witt, L. Wood, B. K. Srivastava, D. L. Olson, W. Caskey, N. T. B. Stone, M. Justice, N. T. Porile, R. L. McGrath, L. S. Schroeder, Lei Huo, C. Pinkenburg, Z. Milosevich, T. Wienold, and Morton Kaplan

Subjects
Physics, Nuclear physics, Excitation function, Mean field theory, Reaction dynamics, General Physics and Astronomy, Alternating Gradient Synchrotron, Sensitivity (control systems), Atomic physics, Nuclear Experiment, Nuclear matter, Intensity (heat transfer), Energy (signal processing)
Abstract

We present the first excitation function of ${\ensuremath{\pi}}^{\ensuremath{-}}$ intensity interferometry at Alternating Gradient Synchrotron (AGS) energies (2--8 A GeV). The sensitivity of the multidimensional correlation functions to the geometry and dynamics of the pion-emitting system provides a stringent test of transport models of heavy ion collisions. Detailed comparisons with a realistic transport model, both with and without an explicit nuclear mean field, suggest that the beam energy evolution in the reaction dynamics is different in the model than in the data. A significantly increased ${\ensuremath{\pi}}^{\ensuremath{-}}$ emission time scale, which has been suggested as a signal of the onset of the transition to quark-gluon plasma, is not observed.

Published
2000

29. The PHOBOS experiment at the RHIC collider

Author

Judith M. Katzy, B. Back, M.D. Baker, D. Barton, R. Betts, A. Białas, A. Budzanowski, W. Busza, A. Carroll, Y.-H. Chang, A.E. Chen, T. Coghen, W. Czyż, M.P. Decowski, M. Friedl, K. Gałuszka, R. Ganz, E. Garcia-Solis, N. George, J. Godlewski, K.H. Gulbrandsen, S. Gushue, C. Halliwell, A. Hayes, G. Heintzelman, R. Hołyński, B. Holzman, U. Jagadish, E. Johnson, J. Kotuła, W. Kucewicz, P. Kulinich, M. Lemler, W.T. Lin, S. Manly, D. McLeod, J. Michałowski, A. Mignerey, J. Mülmenstädt, M. Neal, R. Nouicer, A. Olszewski, R. Pak, I. Park, H. Pernegger, M. Plesko, L.P. Remsberg, M. Reuter, G. Roland, L. Rosenberg, P. Sarin, P. Sawicki, P.J. Stanskas, G.S.F. Stephans, M. Stodulski, A. Sukhanov, A. Trzupek, G. Van Nieuwenhuizen, C. Vale, R. Verdier, B. Wadsworth, F. Wolfs, B. Wosiek, K. Woźniak, A. Wuosmaa, B. Wysłouch, and K. Zalewski

Subjects
Physics, Nuclear and High Energy Physics, Particle physics, Physics::Instrumentation and Detectors, Hadron, Observable, Particle identification, Particle detector, law.invention, Semiconductor detector, Nuclear physics, law, Quark–gluon plasma, High Energy Physics::Experiment, Nuclear Experiment, Collider, Relativistic Heavy Ion Collider
Abstract

PHOBOS is a compact silicon detector designed to study the physics of Au - Au collisions at a center-of-mass energy of 200 A GeV at the Relativistic Heavy Ion Collider. The main goal of the PHOBOS experiment is a comprehensive study of various hadronic observables that should reveal the onset of new phenomena expected to occur in central collisions of gold nuclei. In this paper the detector and the physics program of the PHOBOS experiment is presented.

Published
1999

30. Results from the experiment E895 at the BNL AGS

Author

N. T. Porile, M. A. Lisa, P. Chung, J. L. Romero, S. Y. Panitkin, D. Keane, N T B Stone, Y. M. Liu, G. Rai, Yufeng Zhang, S. Gushue, K. Crowe, R. P. Scharenberg, N.N. Ajitanand, T. Case, J. Klay, Brian Cole, G. Odyniec, D. Best, D. L. Olson, R. L. McGrath, T. Wienold, Morton Kaplan, J. L. Chance, R. Lacey, David Krofcheck, M. Heffner, D. Cebra, J. C. Kintner, C. Pinkenburg, J. Whitfield, L. Wood, W. Caskey, Z. Milosevich, James Alexander, T. J. M. Symons, E. L. Hjort, X. Yang, L. S. Schroeder, Andrew S. Hirsch, M. Anderson, R. Witt, M. Justice, W. N. Zhang, M.L. Gilkes, Hans Georg Ritter, S. Wang, F. P. Brady, B. K. Srivastava, L. Huo, R. Wells, A. C. Das, H. Liu, and J. E. Draper

Subjects
Physics, Nuclear and High Energy Physics, Particle physics, Time projection chamber, Physics::Instrumentation and Detectors, Detector, Observable, Context (language use), Particle identification, Nuclear physics, Nuclear Experiment, Event (particle physics), Beam (structure), Excitation
Abstract

We present some of the latest results from the E895 experiment conducted at the BNL AGS accelerator. Au+Au collisions were recorded by the EOS Time Projection Chamber (TPC) at beam energies of 2, 4, 6, and 8 A GeV. The TPC detector permitted the reconstruction of individual collision events with almost 4π acceptance and good particle identification. This capability allowed E895 to study global observables and two particle correlations with respect to symmetries of the event. Flow excitation functions are examined and discussed in the context of the Nuclear Equation of State.

Published
1999

31. Particle production at the AGS: an excitation function

Author

J.C. Dunlop, L. Ahle, Y. Akiba, K. Ashktorab, M.D. Baker, D. Beavis, H.C. Britt, J. Chang, C. Chasman, Z. Chen, Y.Y. Chu, T. Chujo, V. Cianciolo, B.A. Cole, H.J. Crawford, J.B. Cumming, R. Debbe, W. Eldredge, J. Engelage, S.-Y. Fung, E. Garcia, S. Gushue, H. Hamagaki, L. Hansen, R.S. Hayano, G. Heintzelman, E. Judd, J. Kang, E.-J. Kim, A. Kumagai, K. Kurita, J.-H. Lee, J. Luke, Y. Miake, A. Mignerey, B. Moskowitz, M. Moulson, C. Muentz, S. Nagamiya, K. Nagano, M.N. Namboodiri, C.A. Ogilvie, J. Olness, K. Oyama, L.P. Remsberg, H. Sako, T.C. Sangster, R. Seto, J. Shea, K. Shigaki, R. Soltz, S.G. Steadman, G.S.F. Stephans, T. Tamagawa, M.J. Tannenbaum, J.H. Thomas, S. Ueno-Hayashi, F. Videbæk, F. Wang, Y. Wu, H. Xiang, G.H. Xu, K. Yagi, H. Yao, W.A. Zajc, F. Zhu, B. Back, R.R. Betts, W.C. Chang, C.Y. Chi, S.Y. Fung, R. Ganz, A. Gillitzer, W.F. Henning, D.J. Hofman, B. Holzman, J.H. Kang, E.J. Kim, S.Y. Kim, Y. Kwon, D. McLeod, A.C. Mignerey, V. Nanal, R. Pak, A. Ruangma, D. Russ, P.J. Stanskas, H.Q. Wang, F.L.H. Wolfs, A.H. Wuosmaa, and C.M. Zou

Subjects
Physics, Excitation function, Nuclear physics, Nuclear and High Energy Physics, Differential invariant, High Energy Physics::Experiment, Multiplicity (chemistry), Atomic physics, Nuclear Experiment, Collision, Kinetic energy, Beam energy
Abstract

Experiments E866 and E917 at the AGS have measured the differential invariant yields of positive and negative charged kaons from Au+Au collisions at beam kinetic energies in the laboratory of 2, 4, 6, 8, and 10.8 A·GeV. At each beam energy, a multiplicity array is used to select on the centrality of the collision.

Published
1999

32. HeatingA197uNuclei with8GeV/cAntiproton andπ−Beams

Author

L. P. Remsberg, E. M. Winchester, T. Lefort, Luc Beaulieu, E. Martin, B. B. Back, Kris Kwiatkowski, Ralph G. Korteling, V. E. Viola, W. C. Hsi, L. Pienkowski, A. Ruangma, S. Gushue, E. Ramakrishnan, Douglas J. Rowland, Sherry Yennello, H. Breuer, and Richard Laforest

Subjects
Physics, Silicon, General Physics and Astronomy, chemistry.chemical_element, Nuclear physics, Antiproton beam, Pion, chemistry, Antiproton, Pi, Physics::Accelerator Physics, High Energy Physics::Experiment, Atomic physics, Nuclear Experiment, Excitation, Energy (signal processing), Beam (structure)
Abstract

Comparison of the heating effect produced by 8 GeV/c {pi}{sup -} and antiproton beams incident on {sup 197}Au nuclei has been conducted with the Indiana silicon sphere 4{pi} detector array. Event reconstruction indicates formation of thermal-like heavy residues with excitation energies up to 1.7 GeV. Enhanced energy deposition is observed for antiprotons relative to negative pions. For events with excitation energies that exceed 1000 MeV, there is a 50% increase in cross section for the antiproton beam relative to the {pi}{sup -} beam. The predominant decay mode at these high excitation energies is multifragmentation in which three or more Z{>=}3 fragments are emitted. (c) 1999 The American Physical Society.

Published
1999

33. Elliptic Flow: Transition from Out-of-Plane to In-Plane Emission inAu+AuCollisions

Author

M. L. Gilkes, Wei Zhang, R. Witt, D. Keane, P. Chung, J. Lauret, James Alexander, J. Whitfield, J. L. Chance, S. Y. Panitkin, D. Cebra, N. T. Porile, K. Crowe, R. L. McGrath, Pol Bernard Gossiaux, Pawel Danielewicz, J. C. Kintner, H. G. Ritter, M. Heffner, W. Caskey, L. S. Schroeder, J. L. Romero, G. Rai, A. C. Das, R. P. Scharenberg, H. Liu, M. A. Lisa, Roy A. Lacey, J. Klay, D. Best, N T B Stone, Brian Cole, D. L. Olson, G. Odyniec, C. Law, E. L. Hjort, L. Wood, F. P. Brady, S. Gushue, C. Pinkenburg, T. Case, J. E. Draper, David Krofcheck, M. Justice, Y. M. Liu, T. J. M. Symons, M. Anderson, B. K. Srivastava, L. Huo, Andrew S. Hirsch, N. N. Ajitanand, A. Elmaani, Z. Milosevich, T. Wienold, and Morton Kaplan

Subjects
Physics, Excitation function, Range (particle radiation), Proton, 010308 nuclear & particles physics, Nuclear Theory, Elliptic flow, General Physics and Astronomy, 7. Clean energy, 01 natural sciences, Boltzmann equation, Out of plane, Nuclear physics, Baryon, 0103 physical sciences, Physics::Accelerator Physics, Atomic physics, Nuclear Experiment, 010306 general physics, Beam (structure)
Abstract

We have measured the proton elliptic flow excitation function for the Au + Au system spanning the beam energy range 2 -- 8 AGeV. The excitation function shows a transition from negative to positive elliptic flow at a beam energy, $E_{tr} \sim$ 4 AGeV. Detailed comparisons with calculations from a relativistic Boltzmann-equation are presented. The comparisons suggest a softening of the nuclear equation of state (EOS) from a stiff form (K \sim 380 MeV) at low beam energies (E_{Beam} \le 2 AGeV) to a softer form (K \sim 210 MeV) at higher energies (E_{Beam} \ge $ 4 AGeV) where the calculated baryon density $ \rho \sim 4 \rho_0$.

Published
1999

34. Multifragmentation with GeV light-ion beams

Author

L. P. Remsberg, David S. Ginger, S. Gushue, Douglas J. Rowland, C. Volant, W. G. Lynch, L. Pienkowski, E. Renshaw Foxford, E. C. Pollacco, H. Breuer, K. B. Morley, T. Lefort, N.R. Yoder, V. E. Viola, J. Brzychezyk, E. Ramakrishnan, F. Gimeno-Nogues, G. Wang, W. C. Hsi, E. M. Winchester, R. Legrain, Richard Laforest, Ralph G. Korteling, A. Ruangma, D. S. Bracken, A. Botvina, Hongfei Xi, Sherry Yennello, E. Martin, W. A. Friedman, E. Cornell, M. B. Tsang, and Kris Kwiatkowski

Subjects
Nuclear physics, Physics, Nuclear and High Energy Physics, Antiproton beam, Atomic physics, Nuclear Experiment, Breakup, Deposition (chemistry), Ion
Abstract

Multifragmentation studies with GeV light-ion beams indicate that for the most violent collisions, complex fragments are emitted during expansion of the hot source, followed by near simultaneous breakup of the system near ρ/ρ 0 ∼ 1/3. The results are compared with hybrid INC/EES and INC/SMM models. Preliminary data for the 8 GeV/c π − and preactions on 197 Au show enhanced deposition energy for the antiproton beam.

Published
1999

35. The large momentum transfer reaction 12C(p,2p + n) as a new method for measuring short range NN correlations in nuclei

Author

E. Kosonovsky, M. Tanaka, Misak Sargsian, J. Y. Wu, Y. I. Makdisi, S. Gushue, S. Heppelmann, Yael Mardor, D. S. Barton, J. J. Russell, C. S. Sutton, Marvin L Marshak, Israel Mardor, E. D. Minor, Nelson Christensen, H. Nicholson, J. Alster, J. Aclander, Thomas Roser, S. Durrant, C. White, H. Courant, A. S. Carroll, E. Piasetzky, G. Bunce, and I. Navon

Subjects
Physics, Nuclear physics, Triple coincidence, Nuclear and High Energy Physics, Momentum (technical analysis), Range (particle radiation), Proton, Nuclear Theory, Momentum transfer, Neutron, Nuclear Experiment, Wave function, Beam (structure)
Abstract

The reaction 12 C( p ,2 p + n ) was measured for momentum transfers of 4.8 and 6.2 (GeV/c) 2 at beam momenta of 5.9 and 7.5 GeV/c. We measured the quasi-elastic reaction ( p ,2 p ) at θ cm ⋍ 90°, in a kinematically complete measurement. The neutron momentum was measured in triple coincidence with the two emerging high momentum protons. We present the correlation between the momenta of the struck target proton and the neutron. The events are associated with the high momentum components of the nuclear wave function. We present sparse data which, combined with a quasi elastic description of the ( p ,2 p ) reaction and kinematical arguments, point to a novel way for isolating two-nucleon short range correlations.

Published
1999

36. Simultaneous multiplicity and forward energy characterization of particle spectra in Au+Au collisions at11.6AGeV/c

Author

J.W. Olness, Alice Mignerey, E.-J. Kim, R. A. Soltz, S. Gushue, J. Luke, K. Yagi, M. N. Namboodiri, W. Eldredge, C. Chasman, Jongmin Lee, J. Engelage, Ryugo S. Hayano, S. Nagamiya, Kenta Shigaki, C. Y. Chi, K. Ashktorab, Y. D. Wu, E. Garcia, D. R. Beavis, A. Kumagai, F. Zhu, K. Kurita, S. Ueno-Hayashi, H. B. Yao, L. P. Remsberg, Y. Y. Chu, W. A. Zajc, Y. Akiba, J. H. Kang, M. J. Tannenbaum, R. Seto, B. Moskowitz, M. D. Baker, H. J. Crawford, Brian Cole, C. A. Ogilvie, M. Moulson, Yasuo Miake, S. Y. Fung, Z. Chen, J. H. Thomas, V. Cianciolo, Fuqiang Wang, T. C. Sangster, J. Shea, G. Heintzelman, H. C. Britt, H. Xiang, E. G. Judd, H. Sako, J. C. Dunlop, George Stephans, F. Videbæk, J. Chang, R. R. Debbe, S. G. Steadman, G. H. Xu, Luisa F. Hansen, L. Ahle, J. B. Cumming, C. Muentz, and Hideki Hamagaki

Subjects
Physics, Nuclear physics, Nuclear and High Energy Physics, Particle physics, Pion, Proton, Physics beyond the Standard Model, Observable, Multiplicity (chemistry), Nuclear Experiment, Event (particle physics), Energy (signal processing), Spectral line
Abstract

In this paper Au+Au collisions at 11.6A GeV/c are characterized by two global observables: the energy measured near zero degrees (E{sub ZCAL}) and the total event multiplicity. Particle spectra are measured for different event classes that are defined in a two-dimensional grid of both global observables. For moderately central events ({sigma}/{sigma}{sub int}{lt}12{percent}) the proton dN/dy distributions do not depend on E{sub ZCAL} but only on the event multiplicity. In contrast the shape of the proton transverse spectra shows little dependence on the event multiplicity. The change in the proton dN/dy distributions suggests that different conditions are formed in the collision for different event classes. These event classes are studied for signals of new physics by measuring pion and kaon spectra and yields. In the event classes doubly selected on E{sub ZCAL} and multiplicity there is no indication of any unusual pion or kaon yields, spectra, or K/{pi} ratio even in the events with extreme multiplicity. {copyright} {ital 1999} {ital The American Physical Society}

Published
1999

37. Nuclear Transparency in Large Momentum Transfer Quasielastic Scattering

Author

E. D. Minor, Y. I. Makdisi, S. Durrant, J. J. Russell, Marvin L Marshak, M. Tanaka, A. S. Carroll, T. Roser, J. Alster, S. Heppelmann, Nelson Christensen, S. Gushue, Eli Piasetzky, I. Navon, D. S. Barton, H. Nicholson, G. Bunce, J. Aclander, C. White, Israel Mardor, H. Courant, E. Kosonovsky, J. Y. Wu, and Yael Mardor

Subjects
Physics, Momentum, Quasielastic scattering, Cross section (physics), Deuterium, Degree (graph theory), Nuclear transparency, Scattering, Momentum transfer, General Physics and Astronomy, Atomic physics
Abstract

We measured simultaneously pp elastic and quasielastic (p,thinsp2p) scattering in hydrogen, deuterium, and carbon for momentum transfers of 4.8 to 6.2 (GeV/c){sup 2} at incoming momenta of 5.9 and 7.5 GeV/c and center-of-mass scattering angles in the range {theta}{sub c.m.}=83.7{degree} {endash}90{degree} . The nuclear transparency is defined as the ratio of the quasielastic cross section to the free pp cross section. At incoming momentum of 5.9 GeV/c , the transparency of carbon decreases by a factor of 2 from {theta}{sub c.m.}{approx_equal}85{degree} to {theta}{sub c.m.}{approx_equal}89{degree} . At the largest angle the transparency of carbon increases from 5.9 to 7.5 GeV/c by more than 50{percent}. The transparency in deuterium does not depend on incoming momentum nor on {theta}{sub c.m.} . {copyright} {ital 1998} {ital The American Physical Society }

Published
1998

38. Kaon production in Au+Au collisions at11.6A GeV/c

Author

J. Luke, Alice Mignerey, L. P. Remsberg, J. H. Kang, F. Zhu, M. D. Baker, H. C. Britt, R. R. Debbe, Y. Y. Chu, B. Cole, S. G. Steadman, C. A. Ogilvie, G. H. Xu, G. Heintzelman, F. Videbæk, J. Chang, K. Kurita, Yasuo Miake, J.W. Olness, J. Engelage, H. Hamagaki, R. Seto, M. J. Tannenbaum, Z. Chen, L. Ahle, B. Moskowitz, S. Ueno-Hayashi, V. Cianciolo, K. Yagi, M. N. Namboodiri, Ryugo S. Hayano, Fuqiang Wang, H. J. Crawford, Kenta Shigaki, C. Y. Chi, Luisa F. Hansen, J. H. Thomas, D. R. Beavis, C. Chasman, T. C. Sangster, Y. Akiba, Jongmin Lee, E. G. Judd, R. A. Soltz, S. Gushue, A. Kumagai, E.-J. Kim, H. Xiang, K. Ashktorab, C. Muentz, J. B. Cumming, J. Shea, H. Sako, H. B. Yao, J. C. Dunlop, E. Garcia, George Stephans, S. Nagamiya, Y. D. Wu, S. Y. Fung, W. A. Zajc, W. Eldredge, and M. Moulson

Subjects
Physics, Nuclear physics, Nuclear reaction, Nuclear and High Energy Physics, Nuclear Theory, Quark model, Hadron, Inverse, Production (computer science), Rapidity, Nuclear Experiment, Energy (signal processing), Spectral line
Abstract

A systematic study of the spectra and yields of K{sup +} and K{sup {minus}} is reported by experiment E866 as a function of centrality in Au+Au collisions at 11.6A GeV/c. The invariant transverse spectra for both kaon species are well described by exponentials in m{sub t}, with inverse slope parameters that are largest at midrapidity and which increase with centrality. The inverse slopes of the K{sup +} spectra are slightly larger than the inverse slopes of the K{sup {minus}} spectra. The kaon rapidity density peaks at midrapidity with the K{sup +} distribution wider in rapidity than K{sup {minus}}. The integrated total yields of K{sup +} and K{sup {minus}} increase nonlinearly and steadily with the number of projectile participants. The yield per participant for kaons is two to three times larger than the yield from N-N collisions. This enhancement suggests that the majority of kaons in central Au+Au reactions are produced in secondary hadronic collisions. There is no evidence for an onset of additional kaon production from a possible small volume of baryon-rich quark-gluon plasma. The differences between K{sup +} and K{sup {minus}} rapidity distributions and transverse spectra are consistent with a lower phase space for K{sup {minus}} production due tomore » a higher energy threshold. These differences also exclude simple thermal models that assume emission from a common equilibrated system. {copyright} {ital 1998} {ital The American Physical Society}« less

Published
1998

39. Measurement of quasi-elastic C(p,2p) scattering at high momentum transfer

Author

E. Kosonovsky, J. Alster, C. S. Sutton, Y. I. Makdisi, G. Bunce, Thomas Roser, Eli Piasetzky, J. J. Russell, S. Gushue, S. Heppelmann, Yael Mardor, J. Aclander, I. Navon, E. D. Minor, Nelson Christensen, C. White, H. Nicholson, Marvin L Marshak, H. Courant, D. S. Barton, Israel Mardor, S. Durrant, M. Tanaka, J. Y. Wu, and A. S. Carroll

Subjects
Physics, Nuclear and High Energy Physics, Missing energy, Proton, Scattering, Nuclear Theory, Nuclear physics, Momentum, symbols.namesake, symbols, Physics::Accelerator Physics, Fermi–Dirac statistics, Center of mass, Nuclear Experiment, Fermi gas, Fermi Gamma-ray Space Telescope
Abstract

We measured the high-momentum quasi-elastic 12C(p,2p) reaction (at center of mass angle near 90 degrees) for 6 and 7.5 GeV/c incident protons. The three-momentum components of both final state protons were measured and the missing energy and momentum of the target proton in the nucleus were determined. The validity of the quasi-elastic picture was verified up to Fermi momenta of about 450 MeV/c, where it might be questionable. Transverse and longitudinal Fermi momentum distributions of the target proton were measured and compared to independent particle models which do not reproduce the large momentum tails. We also observed that the transverse Fermi distribution gets wider as the longitudinal component increases in the beam direction, in contrast to a simple Fermi gas model.

Published
1998

40. Antiproton Production inAu+AuCollisions at11.7AGeV/c

Author

Ryugo S. Hayano, J. Chang, Kenta Shigaki, F. Zhu, S. Y. Fung, J. C. Dunlop, H. Sako, J. B. Cumming, L. P. Remsberg, J. H. Kang, S. Nagamiya, Yang Wu, R. A. Soltz, Brian Cole, S. Gushue, K. Kurita, D. R. Beavis, J. Luke, H. Xiang, J.W. Olness, C. Chasman, K. Ashktorab, W. A. Zajc, L. Ahle, J. H. Thomas, Jongmin Lee, T. C. Sangster, E. Garcia, R. Seto, V. Cianciolo, M. D. Baker, S. Ueno-Hayashi, F. Videbæk, C. Muentz, R. R. Debbe, J. Engelage, Y. Y. Chu, J. Shea, S. G. Steadman, C. A. Ogilvie, C. Y. Chi, M. Moulson, G. H. Xu, George Stephans, Yasuo Miake, Fuqiang Wang, E. G. Judd, E. J. Kim, Hideki Hamagaki, Luisa F. Hansen, G. Heintzelman, Z. Chen, H. Yao, W. Eldredge, A. Kumagai, M. J. Tannenbaum, H. J. Crawford, Alice Mignerey, H. C. Britt, Y. Akiba, B. Moskowitz, K. Yagi, and M. N. Namboodiri

Subjects
Physics, Nuclear Theory, Nuclear structure, General Physics and Astronomy, Kinetic energy, Nuclear matter, Nuclear physics, Antiproton, Antimatter, High Energy Physics::Experiment, Atomic physics, Nuclear Experiment, Nucleon, Scaling
Abstract

Antiproton production in 11.7A GeV/c Au+Au collisions over a wide transverse-mass coverage was studied using the AGS-E866 experimental apparatus. The mean transverse kinetic energy increases as a function of centrality and is similar to that of protons. The antiproton yields in Si+Al , Si+Au , and Au+Au collisions are consistent with scaling with the 0.7 power of the number of participant nucleons. Copyright 1998, The American Physical Society

Published
1998

41. Strange particle production and an H-dibaryon search in p-A collisions at the AGS

Author

Y. H. Shin, M. Moulson, Kenneth Francis Read, Yufeng Zhang, R.L. McGrath, A. D. Frawley, S. P. Sorensen, M. L. Gilkes, E. P. Hartouni, N. Namboodiri, R. A. Soltz, Ju Hwan Kang, M. Rosati, Harold Kirk, I. Chemakin, Richard C. Fernow, D. Winter, X. Yang, J. H. Thomas, N. Maeda, W. A. Zajc, L. R. Remsberg, V. Cianciolo, Y. Torun, D. P. Morrison, H. Hiejima, Saskia Mioduszewski, S. Gushue, B.A. Cole, M. Justice, D. Keane, and G. Rai

Subjects
Nuclear physics, Physics, Nuclear and High Energy Physics, Strange quark
Published
1998

42. Collective flow in Au+Au collisions between 2–8 A GeV at AGS

Author

G. Odyniec, R. Scharenberg, J. Chance, D. Krofcheck, T. Case, P. Chung, B. Srivastava, J. Draper, L. Wood, D.A. Cebra, T. Wienold, H. Liu, A. Das, L. Huo, D. Best, J. Kintner, N.T.B. Stone, N.N. Ajitanand, M. Kaplan, D. Keane, L. Schroeder, J. Romero, H.G. Ritter, C. Pinkenburg, M. Gilkes, T.J.M. Symons, M. Heffner, Z. Milosevich, A.S. Hirsch, J. Alexander, R. Lacey, S. Wang, W.N. Zhang, D. Olson, N. Porile, Y. Zhang, K. Crowe, M. Justice, Y. M. Liu, R. McGrath, E. Hjort, W. Caskey, X. Yang, S. Y. Panitkin, J. Whitfield, M. Lisa, S. Gushue, B. Cole, F.P. Brady, and G. Rai

Subjects
Physics, Nuclear physics, Nuclear and High Energy Physics, Mean field theory, Flow (mathematics), Transverse momentum, Observable, Function (mathematics), Statistical physics, Nuclear Experiment, Beam energy
Abstract

The E895 collaboration has undertaken a systematic and exclusive study of Au+Au collisions between 2–8 A GeV. We present preliminary results on collective flow observables as a function of beam energy. Data are compared with theoretical predictions.

Published
1998

43. Centrality and collision system dependence of antiproton production from p+A to Au+Au collisions at AGS Energies

Author

L. Ahle, Y. Akiba, K. Ashktorab, M.D. Baker, D. Beavis, H.C. Britt, J. Chang, C. Chasman, Z. Chen, Y.Y. Chu, V. Cianciolo, B.A. Cole, H.J. Crawford, J.B. Cumming, R. Debbe, J.C. Dunlop, W. Eldredge, J. Engelage, S.-Y. Fung, E. Garcia, S. Gushue, H. Hamagaki, L. Hansen, R.S. Hayano, G. Heintzelman, E. Judd, J. Kang, E.-J. Kim, A. Kumagai, K. Kurita, J.-H. Lee, J. Luke, Y. Miake, A. Mignerey, B. Moskowitz, M. Moulson, C. Muentz, S. Nagamiya, M.N. Namboodiri, C.A. Ogilvie, J. Olness, L.P. Remsberg, H. Sako, T.C. Sangster, R. Seto, J. Shea, K. Shigaki, R. Soltz, S.G. Steadman, G.S.F. Stephans, M.J. Tannenbaum, J.H. Thomas, S. Ueno-Havashi, F. Videb˦k, F. Wang, Y. Wu, H. Xiang, G.H. Xu, K. Yagi, H. Yao, W.A. Zajc, and F. Zhu

Subjects
Physics, Nuclear reaction, Nuclear and High Energy Physics, Antiparticle, Particle physics, Annihilation, Nuclear Theory, Hadron, Nuclear physics, Baryon, Antiproton, Antimatter, Physics::Accelerator Physics, High Energy Physics::Experiment, Physics::Atomic Physics, Nuclear Experiment, Nucleon
Abstract

Antiproton production in heavy ion collisions reflects subtle interplay between initial production and absorption by nucleons. Because the AGS energies (10--20 A(center-dot)GeV/c) are close to the antiproton production threshold, antiproton may be sensitive to cooperative processes such as QGP and hadronic multi-step processes. On the other hand, antiproton has been proposed as a probe of baryon density due to large N(anti N) annihilation cross sections. Cascade models predict the maximum baryon density reaches about 10 times the normal nucleus density in central Au+Au collisions, where the strong antiproton absorption is expected. In this paper, the authors show systematic studies of antiproton production from p+A to Au+Au collisions.

Published
1998

44. Sideways-peaked angular distributions in hadron-induced multifragmentation: Shock waves, geometry, or kinematics?

Author

F. Gimeno-Nogues, K. Kwiatkowski, G. Wang, W. A. Friedman, W. G. Lynch, H. Breuer, W.-c. Hsi, Ralph G. Korteling, V. E. Viola, Hongfei Xi, S. Gushue, E. Cornell, Douglas J. Rowland, D. S. Bracken, M. B. Tsang, A. Botvina, R. Huang, Sherry Yennello, David S. Ginger, N.R. Yoder, K. B. Morley, L. P. Remsberg, and E. Ramakrishnan

Subjects
Nuclear physics, Shock wave, Physics, Nuclear and High Energy Physics, Recoil, Cascade, Hadron, Multiplicity (chemistry), Atomic physics, Nuclear Experiment, Breakup, Kinetic energy, Nuclear matter
Abstract

Exclusive studies of sideways-peaked angular distributions for intermediate-mass fragments (IMFs) produced in hadron-induced reactions have been performed with the Indiana silicon sphere (ISiS) detector array. The effect becomes prominent for beam momenta above about 10thinspGeV/c. Both the magnitude of the effect and the peak angle increase as a function of fragment multiplicity and charge. When gated on IMF kinetic energy, the angular distributions evolve from forward peaked to nearly isotropic as the fragment energy decreases. Fragment-fragment correlation studies show no evidence for a preferred angle that might signal a fast dynamic breakup mechanism. Moving-source and intranuclear cascade simulations suggest a possible kinematic origin arising from significant transverse momentum imparted to the recoil nucleus during the fast cascade. A two-step cascade and statistical multifragmentation calculation is consistent with the data. {copyright} {ital 1998} {ital The American Physical Society}

Published
1998

45. Proton, deuteron, and triton emission at target rapidity in Au+Au collisions at10.20AGeV: Spectra and directed flow

Author

K. Ashktorab, Fuqiang Wang, S. Homma, S. Ueno-Hayashi, B. Moskowitz, M. Moulson, R. A. Soltz, H. Sako, Y. D. Wu, T. C. Sangster, K. Kurita, S. Gushue, R. Seto, T. Sung, J. Luke, W. A. Zajc, Daniel S. Zachary, Hideki Hamagaki, D. R. Beavis, V. Cianciolo, M. Gonin, Q. Zhu, M. J. LeVine, M. J. Tannenbaum, Ryugo S. Hayano, L. Hansen, F. Zhu, E. G. Judd, Y. Y. Chu, C. Chasman, H. J. Crawford, J. Engelage, F. Videbæk, J. Chang, Kenta Shigaki, C. Y. Chi, L. P. Remsberg, S. Y. Fung, J. H. Kang, J. B. Cumming, S. Nagamiya, J. J. Gaardhoje, M. D. Baker, Z. Chen, Brian Cole, A. Kumagai, W. Eldredge, T. K. Nayak, J. H. Thomas, G. Heintzelman, H. C. Britt, J.W. Olness, D. S. Woodruff, C. A. Ogilvie, George Stephans, Yasuo Miake, Y. Wang, Y. Akiba, S. Tonse, K. Yagi, M. N. Namboodiri, L. Ahle, Alex Hansen, H. Kaneko, R. R. Debbe, S. G. Steadman, and G. H. Xu

Subjects
Physics, Nuclear and High Energy Physics, Proton, Nuclear Theory, Spectral line, Nuclear physics, Hodoscope, Deuterium, Pseudorapidity, Rapidity, Emission spectrum, Atomic physics, Nuclear Experiment, Energy (signal processing)
Abstract

Systematic results are presented on proton, deuteron, and triton emission from the target spectator region in collisions of 10.20A GeV gold projectiles with a gold target. A forward hodoscope utilizes detection of projectile spectator fragments to determine the orientation of the reaction plane, event by event. The directed flow {l_angle}p{sub x}{r_angle} is determined as a function of pseudorapidity. Projectile spectator energy is used to estimate impact parameters. Results are compared to current theoretical models ARC, ART, and RQMD. In all cases good agreement with theory is obtained for calculations utilizing a pure cascade without nuclear potential contributions. {copyright} {ital 1998} {ital The American Physical Society}

Published
1998

46. Multifragmentation: thermal vs. dynamic effects

Author

F. Gimeno-Nogues, L. P. Remsberg, E. Cornell, V. E. Viola, S. Gushue, W. G. Lynch, K. B. Morley, D. S. Bracken, W.-c. Hsi, E. Ramakrishnan, C. Volant, K. Kwiatkowski, E. Renshaw Foxford, E. C. Pollacco, M. B. Tsang, David S. Ginger, Ralph G. Korteling, N.R. Yoder, Hongfei Xi, Sherry Yennello, H. Breuer, and G. Wang

Subjects
Nuclear physics, Physics, Nuclear and High Energy Physics, Astrophysics::High Energy Astrophysical Phenomena, Thermal, Hermetic detector, High Energy Physics::Experiment, Atomic physics, Nuclear Experiment, Saturation (chemistry), Beam (structure)
Abstract

Reactions of 1.8 – 4.8 GeV 3He, 5.0 – 9.2 GeV/c π− and 6.0 – 14.6 GeV/c protons with natAg and 197Au targets have been studied with the ISiS 4π detector array. From reconstructed events, excitation-energy distributions have been determined and combined with a 2,3H3,4He isotope-ratio thermometer to study the heating curve for the thermal-like component of these reactions. Dynamic effects also manifest themselves in the data, as evidenced by deposition-energy saturation above ∼5 GeV, IMF emission during expansion, and sideways peaking of the IMF angular distributions for beam energies Eb ≥ 10 GeV.

Published
1998

47. Particle production at high baryon density in central Au+Au reactions at 11.6AGeV/c

Author

T. Sung, Alice Mignerey, S. Tonse, L. Hansen, J. Shea, K. Yagi, M. N. Namboodiri, C. Muentz, C. A. Ogilvie, E. G. Judd, Yasuo Miake, R. R. Debbe, Y. Wang, F. Videbæk, J. Chang, S. G. Steadman, H. Xiang, G. H. Xu, P. Rothschild, J. Luke, M. J. Tannenbaum, S. Nagamiya, K. Ashktorab, Daniel S. Zachary, J. J. Gaardhøje, Hideki Hamagaki, H. J. Crawford, G. Heintzelman, M. Gonin, W. Eldredge, Brian Cole, J. H. Thomas, Q. Zhu, L. Ahle, D. R. Beavis, Alex Hansen, Y. Akiba, M. J. LeVine, J. B. Cumming, E.-J. Kim, H. Kaneko, C. Chasman, H. C. Britt, S. Ueno-Hayashi, B. Moskowitz, Y. Y. Chu, A. Kumagai, Jongmin Lee, E. Garcia, S. Park, Z. Chen, R. A. Soltz, S. Gushue, V. Cianciolo, Fuqiang Wang, T. C. Sangster, K. Kurita, J. Engelage, Ryugo S. Hayano, Kenta Shigaki, C. Y. Chi, L. P. Remsberg, J. H. Kang, M. D. Baker, M. Moulson, F. Zhu, George Stephans, D. P. Morrison, H. Sako, J. C. Dunlop, R. Seto, J.W. Olness, S. Y. Fung, W. A. Zajc, S. Homma, and Y. D. Wu

Subjects
Physics, Nuclear and High Energy Physics, Proton, Nuclear Theory, Nuclear matter, Spectral line, Ion, Nuclear physics, Baryon, Pion, State of matter, Rapidity, Atomic physics, Nuclear Experiment
Abstract

Semi-inclusive proton and pion distributions from central Au+Au reactions at 11.6A GeV/c have been measured. The proton rapidity distribution shows significantly increased stopping compared to lighter systems, providing strong evidence for the formation of a state of matter with baryon density substantially greater than normal nuclear matter. Unlike reactions at this energy induced by lighter heavy ions, at low m{sub t}-m{sub 0} the proton invariant spectra deviate from a single exponential shape and become flatter, while {pi}{sup {minus}} spectra are found to rise faster than the {pi}{sup +} spectra. {copyright} {ital 1998} {ital The American Physical Society}

Published
1998

48. Probing the nuclear EOS with GeV light-ion beams

Author

Hongfei Xi, K.B. Morley, Sherry Yennello, N.R. Yoder, E. C. Pollacco, M. B. Tsang, E. Cornell, E. Renshaw Foxford, Y. Y. Chu, Ralph G. Korteling, L. P. Remsberg, K. Kwiatkowski, J. Brzychczyk, G. Wang, M. J. Huang, R. Legrain, F. Gimeno-Nogues, S. Gushue, W.-c. Hsi, E. Ramakrishnan, H. Breuer, David S. Ginger, Douglas J. Rowland, W. G. Lynch, D. S. Bracken, V. E. Viola, and C. Volant

Subjects
Nuclear physics, Physics, Nuclear and High Energy Physics, Projectile, Nuclear Theory, Atomic physics, Multiplicity (chemistry), Nuclear Experiment, Nucleon, Excitation, Ion
Abstract

The first 4π studies of identified light-charged-particles and IMFs emitted in the p, π − + 197 Au reactions above 5 GeV/c are reported. Multiplicity and angular distributions show little sensitivity to either bombarding energy or projectile type. Excitation energy distributions obtained from data for the 4.8 GeV 3 He + 197 Au reaction yield values up to E ∗ ≲ 1500 MeV and E ∗ A residue ≲ 10 MeV/nucleon . Analysis of large-angle, IMF-IMF correlations for this same system suggests that multifragmentation is a fast, time-dependent process.

Published
1997

49. Two-particle rapidity correlations from the Bose-Einstein effect in central28Si+Au collisions at14.6AGeV/cand intermittency

Author

V. Cianciolo, D. R. Beavis, Fuqiang Wang, D. P. Morrison, S. Hayashi, F. Videbæk, T. Sung, D. Roehrich, J.W. Olness, B. Budick, H. C. Britt, J. Engelage, W. L. Kehoe, Brian Cole, Hiroshi Kaneko, C. G. Parsons, J. H. Thomas, Hiroyoshi Sakurai, Xiaodong Yang, R. Seto, S. Homma, H. E. Wegner, Y. Y. Chu, O. Hansen, C. Y. Chi, S. Tonse, L. P. Remsberg, R. R. Debbe, Daniel S. Zachary, Hideki Hamagaki, M. N. Namboodiri, M. J. Tannenbaum, J. H. Kang, S. G. Steadman, Y. Tanaka, Yang Wu, J. B. Cumming, H. J. Crawford, O. Vossnack, B. Moskowitz, George Stephans, Y. Wang, Y. Akiba, S. B. Kaufman, Yasuo Miake, R. J. Morse, T. C. Sangster, Z. Chen, J. B. Costales, J. H. van Dijk, P. Beery, P. Stankus, R. J. Ledoux, W. A. Zajc, V. Vutsadakis, R. A. Soltz, S. Gushue, M. Gonin, M. J. LeVine, C. Chasman, S. Nagamiya, T. K. Nayak, Ryugo S. Hayano, K. Kurita, P. Rothschild, D. S. Woodruff, and S. Y. Fung

Subjects
Physics, Nuclear and High Energy Physics, symbols.namesake, Strange matter, Particle physics, Pion, Bose–Einstein statistics, Pseudorapidity, Hadron, symbols, Rapidity, Multiplicity (chemistry), Charged particle
Abstract

In previous work, the E802 Collaboration at the BNL-AGS used negative binomial distribution (NBD) fits to charged particle multiplicity distributions from central collisions of {sup 16}O+Cu at 14.6A GeV/c to derive the two-particle short-range rapidity correlation length and strength. These turned out to be much shorter and weaker than the values for hadron collisions, which led to a simple and elegant explanation of intermittency. In the present work, a direct measurement of the two-particle correlation of identified pions in the E802/E859 magnetic spectrometer is performed in the interval 1.5{le}y{le}2.0 for central {sup 28}Si+Au collisions, both in terms of Q{sub inv}={radical}({vert_bar}{rvec q}{vert_bar}{sup 2}{minus}q{sub 0}{sup 2}), where q=p{sub 2}{minus}p{sub 1}=({rvec q},q{sub 0}), and also in terms of {vert_bar}{eta}{sub 2}{minus}{eta}{sub 1}{vert_bar} and {vert_bar}y{sub 2}{minus}y{sub 1}{vert_bar}, where p,{eta}, and {ital y} are the four-momentum, pseudorapidity, and rapidity of the pions. It is demonstrated that the two-pion correlation in rapidity (and pseudorapidity) is entirely due to the Bose-Einstein interference. The directly measured correlation length in both {eta} and {ital y} is {xi}=0.19{plus_minus}0.03 for two {pi}{sup {minus}}, with strength R(0,0){approximately}1{percent}, in agreement with the previous E802 indirect measurements derived from the NBD analysis of intermittency. {copyright} {ital 1997} {ital The American Physical Society}

Published
1997

50. Formation of Hot Nuclei with GeVpandπ−Beams

Author

H. Breuer, M. J. Huang, E. Cornell, L. P. Remsberg, K. Kwiatkowski, K. B. Morley, D. S. Bracken, David S. Ginger, E. Ramakrishnan, G. Wang, V. E. Viola, Ralph G. Korteling, W.-c. Hsi, M. B. Tsang, F. Gimeno-Nogures, W. G. Lynch, S. Gushue, Douglas J. Rowland, Y. Y. Chu, Hongfei Xi, Sherry Yennello, and N.R. Yoder

Subjects
Physics, Hadron, General Physics and Astronomy, Multiplicity (mathematics), Charged particle, Nuclear physics, medicine.anatomical_structure, Fragmentation (mass spectrometry), Cascade, medicine, Atomic physics, Nuclear Experiment, Nucleus, Beam (structure), Excitation
Abstract

4{pi} studies of multiple charged-particle emission in GeV {pi}{sup {minus}} - and proton-induced reactions on a Au target have been performed with the ISiS detector array. Multiplicity, charge, and angular distributions yield nearly identical results for both p and {pi}{sup {minus}} beams, suggesting an independence of hadron type in initiating the fast cascade and subsequent energy deposition in the struck nucleus. The excitation functions show little sensitivity to beam momentum, consistent with a saturation in deposition energy and the concept of limiting fragmentation. However, the intermediate mass fragment multiplicities and fragment charge distributions depend strongly on collision violence. {copyright} {ital 1997} {ital The American Physical Society}

Published
1997

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